diff --git a/code/espurna/build.cpp b/code/espurna/build.cpp
index f7ad3e67..d0872ebf 100644
--- a/code/espurna/build.cpp
+++ b/code/espurna/build.cpp
@@ -69,8 +69,8 @@ Sdk get() {
 namespace hardware {
 namespace internal {
 
-alignas(4) static constexpr char Manufacturer[] PROGMEM = MANUFACTURER;
-alignas(4) static constexpr char Device[] PROGMEM = DEVICE;
+PROGMEM_STRING(Manufacturer, MANUFACTURER);
+PROGMEM_STRING(Device, DEVICE);
 
 } // namespace internal
 
@@ -94,7 +94,7 @@ constexpr Hardware get() {
 namespace app {
 namespace internal {
 
-alignas(4) static constexpr char Modules[] PROGMEM =
+alignas(4) static constexpr char Modules[] PROGMEM_STRING_ATTR =
 #if ALEXA_SUPPORT
     "ALEXA "
 #endif
@@ -240,13 +240,13 @@ alignas(4) static constexpr char Modules[] PROGMEM =
 #endif
     "";
 
-alignas(4) static constexpr char Name[] PROGMEM = APP_NAME;
-alignas(4) static constexpr char Version[] PROGMEM = APP_VERSION;
-alignas(4) static constexpr char Author[] PROGMEM = APP_AUTHOR;
-alignas(4) static constexpr char Website[] PROGMEM = APP_WEBSITE;
+PROGMEM_STRING(Name, APP_NAME);
+PROGMEM_STRING(Version, APP_VERSION);
+PROGMEM_STRING(Author, APP_AUTHOR);
+PROGMEM_STRING(Website, APP_WEBSITE);
 
-alignas(4) static constexpr char BuildDate[] PROGMEM = __DATE__;
-alignas(4) static constexpr char BuildTime[] PROGMEM = __TIME__;
+PROGMEM_STRING(BuildDate, __DATE__);
+PROGMEM_STRING(BuildTime, __TIME__);
 
 } // namespace internal
 
diff --git a/code/espurna/button.cpp b/code/espurna/button.cpp
index 80b43240..0df4983e 100644
--- a/code/espurna/button.cpp
+++ b/code/espurna/button.cpp
@@ -35,32 +35,32 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Gpio[] PROGMEM = "btnGpio";
-alignas(4) static constexpr char GpioType[] PROGMEM = "btnGpioType";
-alignas(4) static constexpr char Provider[] PROGMEM = "btnProv";
-alignas(4) static constexpr char Mode[] PROGMEM = "btnMode";
-alignas(4) static constexpr char DefaultValue[] PROGMEM = "btnDefVal";
-alignas(4) static constexpr char PinMode[] PROGMEM = "btnPinMode";
+PROGMEM_STRING(Gpio, "btnGpio");
+PROGMEM_STRING(GpioType, "btnGpioType");
+PROGMEM_STRING(Provider, "btnProv");
+PROGMEM_STRING(Mode, "btnMode");
+PROGMEM_STRING(DefaultValue, "btnDefVal");
+PROGMEM_STRING(PinMode, "btnPinMode");
 
-alignas(4) static constexpr char Release[] PROGMEM = "btnRlse";
-alignas(4) static constexpr char Press[] PROGMEM = "btnPress";
-alignas(4) static constexpr char Click[] PROGMEM = "btnClick";
-alignas(4) static constexpr char DoubleClick[] PROGMEM = "btnDclk";
-alignas(4) static constexpr char TripleClick[] PROGMEM = "btnTclk";
-alignas(4) static constexpr char LongClick[] PROGMEM = "btnLclk";
-alignas(4) static constexpr char LongLongClick[] PROGMEM = "btnLLclk";
+PROGMEM_STRING(Release, "btnRlse");
+PROGMEM_STRING(Press, "btnPress");
+PROGMEM_STRING(Click, "btnClick");
+PROGMEM_STRING(DoubleClick, "btnDclk");
+PROGMEM_STRING(TripleClick, "btnTclk");
+PROGMEM_STRING(LongClick, "btnLclk");
+PROGMEM_STRING(LongLongClick, "btnLLclk");
 
-alignas(4) static constexpr char DebounceDelay[] PROGMEM = "btnDebDel";
-alignas(4) static constexpr char LongClickDelay[] PROGMEM = "btnLclkDel";
-alignas(4) static constexpr char LongLongClickDelay[] PROGMEM = "btnLLclkDel";
-alignas(4) static constexpr char RepeatDelay[] PROGMEM = "btnRepDel";
+PROGMEM_STRING(DebounceDelay, "btnDebDel");
+PROGMEM_STRING(LongClickDelay, "btnLclkDel");
+PROGMEM_STRING(LongLongClickDelay, "btnLLclkDel");
+PROGMEM_STRING(RepeatDelay, "btnRepDel");
 
-alignas(4) static constexpr char Relay[] PROGMEM = "btnRelay";
+PROGMEM_STRING(Relay, "btnRelay");
 
-alignas(4) static constexpr char MqttSendAll[] PROGMEM = "btnMqttSendAll";
-alignas(4) static constexpr char MqttRetain[] PROGMEM = "btnMqttRetain";
+PROGMEM_STRING(MqttSendAll, "btnMqttSendAll");
+PROGMEM_STRING(MqttRetain, "btnMqttRetain");
 
-[[gnu::unused]] alignas(4) static constexpr char AnalogLevel[] PROGMEM = "btnLevel";
+[[gnu::unused]] PROGMEM_STRING(AnalogLevel, "btnLevel");
 
 } // namespace
 } // namespace keys
@@ -70,17 +70,17 @@ namespace {
 
 using espurna::settings::options::Enumeration;
 
-alignas(4) static constexpr char Switch[] PROGMEM = "switch";
-alignas(4) static constexpr char Pushbutton[] PROGMEM = "pushbutton";
+PROGMEM_STRING(Switch, "switch");
+PROGMEM_STRING(Pushbutton, "pushbutton");
 
 static constexpr std::array<Enumeration<debounce_event::types::Mode>, 2> DebounceEventMode PROGMEM {
     {{debounce_event::types::Mode::Switch, Switch},
      {debounce_event::types::Mode::Pushbutton, Pushbutton}}
 };
 
-alignas(4) static constexpr char Low[] PROGMEM = "low";
-alignas(4) static constexpr char High[] PROGMEM = "high";
-alignas(4) static constexpr char Initial[] PROGMEM = "initial";
+PROGMEM_STRING(Low, "low");
+PROGMEM_STRING(High, "high");
+PROGMEM_STRING(Initial, "initial");
 
 static constexpr std::array<Enumeration<debounce_event::types::PinValue>, 3> DebounceEventPinValue PROGMEM {
     {{debounce_event::types::PinValue::Low, Low},
@@ -88,9 +88,9 @@ static constexpr std::array<Enumeration<debounce_event::types::PinValue>, 3> Deb
      {debounce_event::types::PinValue::Initial, Initial}}
 };
 
-alignas(4) static constexpr char Input[] PROGMEM = "default";
-alignas(4) static constexpr char InputPullup[] PROGMEM = "pull-up";
-alignas(4) static constexpr char InputPulldown[] PROGMEM = "pull-down";
+PROGMEM_STRING(Input, "default");
+PROGMEM_STRING(InputPullup, "pull-up");
+PROGMEM_STRING(InputPulldown, "pull-down");
 
 static constexpr std::array<Enumeration<debounce_event::types::PinMode>, 3> DebounceEventPinMode PROGMEM {
     {{debounce_event::types::PinMode::Input, Input},
@@ -98,9 +98,9 @@ static constexpr std::array<Enumeration<debounce_event::types::PinMode>, 3> Debo
      {debounce_event::types::PinMode::InputPulldown, InputPulldown}}
 };
 
-alignas(4) static constexpr char None[] PROGMEM = "none";
-alignas(4) static constexpr char Gpio[] PROGMEM = "gpio";
-alignas(4) static constexpr char Analog[] PROGMEM = "analog";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(Gpio, "gpio");
+PROGMEM_STRING(Analog, "analog");
 
 static constexpr std::array<Enumeration<ButtonProvider>, 3> ButtonProviderOptions PROGMEM {
     {{ButtonProvider::None, None},
@@ -108,24 +108,24 @@ static constexpr std::array<Enumeration<ButtonProvider>, 3> ButtonProviderOption
      {ButtonProvider::Analog, Analog}}
 };
 
-[[gnu::unused]] alignas(4) static constexpr char Toggle[] PROGMEM = "relay-toggle";
-[[gnu::unused]] alignas(4) static constexpr char On[] PROGMEM = "relay-on";
-[[gnu::unused]] alignas(4) static constexpr char Off[] PROGMEM = "relay-off";
+[[gnu::unused]] PROGMEM_STRING(Toggle, "relay-toggle");
+[[gnu::unused]] PROGMEM_STRING(On, "relay-on");
+[[gnu::unused]] PROGMEM_STRING(Off, "relay-off");
 
-alignas(4) static constexpr char AccessPoint[] PROGMEM = "wifi-ap";
-alignas(4) static constexpr char Reset[] PROGMEM = "reset";
-alignas(4) static constexpr char FactoryReset[] PROGMEM = "factory";
+PROGMEM_STRING(AccessPoint, "wifi-ap");
+PROGMEM_STRING(Reset, "reset");
+PROGMEM_STRING(FactoryReset, "factory");
 
-[[gnu::unused]] alignas(4) static constexpr char BrightnessIncrease[] PROGMEM = "bri-inc";
-[[gnu::unused]] alignas(4) static constexpr char BrightnessDecrease[] PROGMEM = "bri-dec";
+[[gnu::unused]] PROGMEM_STRING(BrightnessIncrease, "bri-inc");
+[[gnu::unused]] PROGMEM_STRING(BrightnessDecrease, "bri-dec");
 
-[[gnu::unused]] alignas(4) static constexpr char DisplayOn[] PROGMEM = "display-on";
+[[gnu::unused]] PROGMEM_STRING(DisplayOn, "display-on");
 
-alignas(4) static constexpr char Custom[] PROGMEM = "custom";
+PROGMEM_STRING(Custom, "custom");
 
-[[gnu::unused]] alignas(4) static constexpr char FanLow[] PROGMEM = "fan-low";
-[[gnu::unused]] alignas(4) static constexpr char FanMedium[] PROGMEM = "fan-medium";
-[[gnu::unused]] alignas(4) static constexpr char FanHigh[] PROGMEM = "fan-high";
+[[gnu::unused]] PROGMEM_STRING(FanLow, "fan-low");
+[[gnu::unused]] PROGMEM_STRING(FanMedium, "fan-medium");
+[[gnu::unused]] PROGMEM_STRING(FanHigh, "fan-high");
 
 static constexpr Enumeration<ButtonAction> ButtonActionOptions[] PROGMEM {
     {ButtonAction::None, None},
@@ -793,7 +793,7 @@ void button(::terminal::CommandContext&& ctx) {
     }
 }
 
-alignas(4) static constexpr char Button[] PROGMEM = "BUTTON";
+PROGMEM_STRING(Button, "BUTTON");
 
 static constexpr ::terminal::Command Commands[] PROGMEM {
     {Button, button},
diff --git a/code/espurna/crash.cpp b/code/espurna/crash.cpp
index f5358c5b..faf1f35b 100644
--- a/code/espurna/crash.cpp
+++ b/code/espurna/crash.cpp
@@ -223,7 +223,7 @@ void dump(Print& print) {
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char Name[] PROGMEM = "CRASH";
+PROGMEM_STRING(Name, "CRASH");
 
 void command(::terminal::CommandContext&& ctx) {
     debug::crash::forceDump(ctx.output);
diff --git a/code/espurna/debug.cpp b/code/espurna/debug.cpp
index 54e7e82e..91a2b43a 100644
--- a/code/espurna/debug.cpp
+++ b/code/espurna/debug.cpp
@@ -36,9 +36,9 @@ namespace {
 
 using espurna::settings::options::Enumeration;
 
-alignas(4) static constexpr char Disabled[] PROGMEM = "off";
-alignas(4) static constexpr char Enabled[] PROGMEM = "on";
-alignas(4) static constexpr char SkipBoot[] PROGMEM = "skip-boot";
+PROGMEM_STRING(Disabled, "off");
+PROGMEM_STRING(Enabled, "on");
+PROGMEM_STRING(SkipBoot, "skip-boot");
 
 static constexpr Enumeration<DebugLogMode> DebugLogModeOptions[] PROGMEM {
     {DebugLogMode::Disabled, Disabled},
@@ -52,13 +52,13 @@ static constexpr Enumeration<DebugLogMode> DebugLogModeOptions[] PROGMEM {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char SdkDebug[] PROGMEM = "dbgSDK";
-alignas(4) static constexpr char Mode[] PROGMEM = "dbgLogMode";
-alignas(4) static constexpr char Buffer[] PROGMEM = "dbgLogBuf";
-alignas(4) static constexpr char BufferSize[] PROGMEM = "dbgLogBufSize";
+PROGMEM_STRING(SdkDebug, "dbgSDK");
+PROGMEM_STRING(Mode, "dbgLogMode");
+PROGMEM_STRING(Buffer, "dbgLogBuf");
+PROGMEM_STRING(BufferSize, "dbgLogBufSize");
 
-alignas(4) static constexpr char HeartbeatMode[] PROGMEM = "dbgHbMode";
-alignas(4) static constexpr char HeartbeatInterval[] PROGMEM = "dbgHbIntvl";
+PROGMEM_STRING(HeartbeatMode, "dbgHbMode");
+PROGMEM_STRING(HeartbeatInterval, "dbgHbIntvl");
 
 } // namespace
 } // namespace keys
@@ -660,7 +660,7 @@ void onBoot() {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char DebugBuffer[] PROGMEM = "DEBUG.BUFFER";
+PROGMEM_STRING(DebugBuffer, "DEBUG.BUFFER");
 
 void debug_buffer(::terminal::CommandContext&& ctx) {
     debug::buffer::disable();
diff --git a/code/espurna/domoticz.cpp b/code/espurna/domoticz.cpp
index dcae69dc..72710044 100644
--- a/code/espurna/domoticz.cpp
+++ b/code/espurna/domoticz.cpp
@@ -116,20 +116,20 @@ constexpr bool enabled() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "dczEnabled";
-alignas(4) static constexpr char TopicOut[] PROGMEM = "dczTopicOut";
-alignas(4) static constexpr char TopicIn[] PROGMEM = "dczTopicIn";
+PROGMEM_STRING(Enabled, "dczEnabled");
+PROGMEM_STRING(TopicOut, "dczTopicOut");
+PROGMEM_STRING(TopicIn, "dczTopicIn");
 
 #if RELAY_SUPPORT
-alignas(4) static constexpr char RelayIdx[] PROGMEM = "dczTopicIn";
+PROGMEM_STRING(RelayIdx, "dczTopicIn");
 #endif
 
 #if SENSOR_SUPPORT
-alignas(4) static constexpr char MagnitudeIdx[] PROGMEM = "dczTopicIn";
+PROGMEM_STRING(MagnitudeIdx, "dczTopicIn");
 #endif
 
 #if LIGHT_PROVIDER != LIGHT_PROVIDER_NONE
-alignas(4) static constexpr char LightIdx[] PROGMEM = "dczLightIdx";
+PROGMEM_STRING(LightIdx, "dczLightIdx");
 #endif
 
 } // namespace keys
@@ -430,7 +430,7 @@ void send(unsigned char index, const espurna::sensor::Value& value) {
 namespace web {
 namespace {
 
-alignas(4) static constexpr char Prefix[] PROGMEM = "dcz";
+PROGMEM_STRING(Prefix, "dcz");
 
 bool onKeyCheck(espurna::StringView key, const JsonVariant&) {
     return espurna::settings::query::samePrefix(key, Prefix);
diff --git a/code/espurna/gpio.cpp b/code/espurna/gpio.cpp
index c6c79280..397e461b 100644
--- a/code/espurna/gpio.cpp
+++ b/code/espurna/gpio.cpp
@@ -410,11 +410,11 @@ namespace options {
 
 using espurna::settings::options::Enumeration;
 
-alignas(4) static constexpr char None[] PROGMEM = "none";
-alignas(4) static constexpr char Hardware[] PROGMEM = "hardware";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(Hardware, "hardware");
 
 #if MCP23S08_SUPPORT
-alignas(4) static constexpr char Mcp23s08[] PROGMEM = "mcp23s08";
+PROGMEM_STRING(Mcp23s08, "mcp23s08");
 #endif
 
 static constexpr Enumeration<GpioType> GpioTypeOptions[] PROGMEM {
@@ -607,7 +607,7 @@ void add(Origin origin) {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char GpioLocks[] PROGMEM = "GPIO.LOCKS";
+PROGMEM_STRING(GpioLocks, "GPIO.LOCKS");
 
 void gpio_list_origins(::terminal::CommandContext&& ctx) {
     for (const auto& origin : origin::internal::origins) {
@@ -620,7 +620,7 @@ void gpio_list_origins(::terminal::CommandContext&& ctx) {
     }
 }
 
-alignas(4) static constexpr char Gpio[] PROGMEM = "GPIO";
+PROGMEM_STRING(Gpio, "GPIO");
 
 void gpio_read_write(::terminal::CommandContext&& ctx) {
     const int pin = (ctx.argv.size() >= 2)
@@ -696,7 +696,7 @@ void gpio_read_write(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char RegRead[] PROGMEM = "REG.READ";
+PROGMEM_STRING(RegRead, "REG.READ");
 
 void reg_read(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 2) {
@@ -712,7 +712,7 @@ void reg_read(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("REG.READ <ADDRESS>"));
 }
 
-alignas(4) static constexpr char RegWrite[] PROGMEM = "REG.WRITE";
+PROGMEM_STRING(RegWrite, "REG.WRITE");
 
 void reg_write(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 3) {
diff --git a/code/espurna/homeassistant.cpp b/code/espurna/homeassistant.cpp
index 70d6f65e..4c1fc11e 100644
--- a/code/espurna/homeassistant.cpp
+++ b/code/espurna/homeassistant.cpp
@@ -32,7 +32,7 @@ namespace {
 
 namespace build {
 
-alignas(4) static constexpr char Prefix[] PROGMEM = HOMEASSISTANT_PREFIX;
+PROGMEM_STRING(Prefix, HOMEASSISTANT_PREFIX);
 
 constexpr StringView prefix() {
     return Prefix;
@@ -51,9 +51,9 @@ constexpr bool retain() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Prefix[] PROGMEM = "haPrefix";
-alignas(4) static constexpr char Enabled[] PROGMEM = "haEnabled";
-alignas(4) static constexpr char Retain[] PROGMEM = "haRetain";
+PROGMEM_STRING(Prefix, "haPrefix");
+PROGMEM_STRING(Enabled, "haEnabled");
+PROGMEM_STRING(Retain, "haRetain");
 
 } // namespace keys
 
@@ -1061,7 +1061,7 @@ namespace web {
 
 #if WEB_SUPPORT
 
-alignas(4) static constexpr char Prefix[] PROGMEM = "ha";
+PROGMEM_STRING(Prefix, "ha");
 
 void onVisible(JsonObject& root) {
     wsPayloadModule(root, Prefix);
@@ -1084,7 +1084,7 @@ bool onKeyCheck(StringView key, const JsonVariant& value) {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char Send[] PROGMEM = "HA.SEND";
+PROGMEM_STRING(Send, "HA.SEND");
 
 void send(::terminal::CommandContext&& ctx) {
     internal::state = internal::State::Pending;
diff --git a/code/espurna/i2c.cpp b/code/espurna/i2c.cpp
index 7c3f8412..07c8ea1f 100644
--- a/code/espurna/i2c.cpp
+++ b/code/espurna/i2c.cpp
@@ -314,7 +314,7 @@ void init() {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char Locked[] PROGMEM = "I2C.LOCKED";
+PROGMEM_STRING(Locked, "I2C.LOCKED");
 
 void locked(::terminal::CommandContext&& ctx) {
     for (size_t address = 0; address < lock::storage.size(); ++address) {
@@ -326,7 +326,7 @@ void locked(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Scan[] PROGMEM = "I2C.SCAN";
+PROGMEM_STRING(Scan, "I2C.SCAN");
 
 void scan(::terminal::CommandContext&& ctx) {
     size_t devices { 0 };
@@ -344,7 +344,7 @@ void scan(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("no devices found"));
 }
 
-alignas(4) static constexpr char Clear[] PROGMEM = "I2C.CLEAR";
+PROGMEM_STRING(Clear, "I2C.CLEAR");
 
 void clear(::terminal::CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("result %d\n"), i2c::clear());
diff --git a/code/espurna/ifan.cpp b/code/espurna/ifan.cpp
index af09c7a6..24dd5ce3 100644
--- a/code/espurna/ifan.cpp
+++ b/code/espurna/ifan.cpp
@@ -29,10 +29,10 @@ namespace settings {
 namespace options {
 namespace {
 
-alignas(4) static constexpr char Off[] PROGMEM = "off";
-alignas(4) static constexpr char Low[] PROGMEM = "low";
-alignas(4) static constexpr char Medium[] PROGMEM = "medium";
-alignas(4) static constexpr char High[] PROGMEM = "high";
+PROGMEM_STRING(Off, "off");
+PROGMEM_STRING(Low, "low");
+PROGMEM_STRING(Medium, "medium");
+PROGMEM_STRING(High, "high");
 
 static constexpr std::array<espurna::settings::options::Enumeration<FanSpeed>, 4> FanSpeedOptions PROGMEM {
     {{FanSpeed::Off, Off},
@@ -285,7 +285,7 @@ private:
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char Speed[] PROGMEM = "SPEED";
+PROGMEM_STRING(Speed, "SPEED");
 
 void speed(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 2) {
diff --git a/code/espurna/influxdb.cpp b/code/espurna/influxdb.cpp
index 67231f84..20d8891e 100644
--- a/code/espurna/influxdb.cpp
+++ b/code/espurna/influxdb.cpp
@@ -279,7 +279,7 @@ bool _idbHeartbeat(espurna::heartbeat::Mask mask) {
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char IdbSend[] PROGMEM = "IDB.SEND";
+PROGMEM_STRING(IdbSend, "IDB.SEND");
 
 static void idbTerminalSend(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 4) {
diff --git a/code/espurna/ir.cpp b/code/espurna/ir.cpp
index 5a693381..1b208a68 100644
--- a/code/espurna/ir.cpp
+++ b/code/espurna/ir.cpp
@@ -1567,7 +1567,7 @@ void process(rx::DecodeResult& result) {
     }
 }
 
-alignas(4) static constexpr char IrSend[] PROGMEM = "IR.SEND";
+PROGMEM_STRING(IrSend, "IR.SEND");
 
 void send(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 2) {
diff --git a/code/espurna/led.cpp b/code/espurna/led.cpp
index 4e475732..a3fff6ba 100644
--- a/code/espurna/led.cpp
+++ b/code/espurna/led.cpp
@@ -365,11 +365,11 @@ bool Led::toggle() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Gpio[] PROGMEM = "ledGpio";
-alignas(4) static constexpr char Inverse[] PROGMEM = "ledInv";
-alignas(4) static constexpr char Mode[] PROGMEM = "ledMode";
-alignas(4) static constexpr char Relay[] PROGMEM = "ledRelay";
-alignas(4) static constexpr char Pattern[] PROGMEM = "ledPattern";
+PROGMEM_STRING(Gpio, "ledGpio");
+PROGMEM_STRING(Inverse, "ledInv");
+PROGMEM_STRING(Mode, "ledMode");
+PROGMEM_STRING(Relay, "ledRelay");
+PROGMEM_STRING(Pattern, "ledPattern");
 
 } // namespace keys
 
@@ -377,20 +377,20 @@ namespace options {
 
 using espurna::settings::options::Enumeration;
 
-alignas(4) static constexpr char Manual[] PROGMEM = "manual";
-alignas(4) static constexpr char WiFi[] PROGMEM = "wifi";
-alignas(4) static constexpr char On[] PROGMEM = "on";
-alignas(4) static constexpr char Off[] PROGMEM = "off";
+PROGMEM_STRING(Manual, "manual");
+PROGMEM_STRING(WiFi, "wifi");
+PROGMEM_STRING(On, "on");
+PROGMEM_STRING(Off, "off");
 
 #if RELAY_SUPPORT
-alignas(4) static constexpr char Relay[] PROGMEM = "relay";
-alignas(4) static constexpr char RelayInverse[] PROGMEM = "relay-inverse";
+PROGMEM_STRING(Relay, "relay");
+PROGMEM_STRING(RelayInverse, "relay-inverse");
 
-alignas(4) static constexpr char FindMe[] PROGMEM = "findme";
-alignas(4) static constexpr char FindMeWiFi[] PROGMEM = "findme-wifi";
+PROGMEM_STRING(FindMe, "findme");
+PROGMEM_STRING(FindMeWiFi, "findme-wifi");
 
-alignas(4) static constexpr char Relays[] PROGMEM = "relays";
-alignas(4) static constexpr char RelaysWiFi[] PROGMEM = "relays-wifi";
+PROGMEM_STRING(Relays, "relays");
+PROGMEM_STRING(RelaysWiFi, "relays-wifi");
 #endif
 
 static constexpr Enumeration<LedMode> LedModeOptions[] PROGMEM {
@@ -991,7 +991,7 @@ void onConnected(JsonObject& root) {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char Led[] PROGMEM = "LED";
+PROGMEM_STRING(Led, "LED");
 
 void led(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
diff --git a/code/espurna/light.cpp b/code/espurna/light.cpp
index df5106b8..4dde18fb 100644
--- a/code/espurna/light.cpp
+++ b/code/espurna/light.cpp
@@ -589,8 +589,8 @@ namespace internal {
 
 template <>
 my92xx_model_t convert(const String& value) {
-    alignas(4) static constexpr char MY9291[] PROGMEM = "9291";
-    alignas(4) static constexpr char MY9231[] PROGMEM = "9231";
+    PROGMEM_STRING(MY9291, "9291");
+    PROGMEM_STRING(MY9231, "9231");
 
     using Options = std::array<espurna::settings::options::Enumeration<my92xx_model_t>, 2>;
     static constexpr Options options {
@@ -2642,7 +2642,7 @@ void _lightNotificationInit(size_t channel) {
     lightState(true);
 }
 
-alignas(4) static constexpr char LightCommandNotify[] PROGMEM = "NOTIFY";
+PROGMEM_STRING(LightCommandNotify, "NOTIFY");
 
 static void _lightCommandNotify(::terminal::CommandContext&& ctx) {
     static constexpr auto NotifyTransition = LightTransition{
@@ -2711,7 +2711,7 @@ static void _lightCommandNotify(::terminal::CommandContext&& ctx) {
     lightSequence(std::move(callbacks));
 }
 
-alignas(4) static constexpr char LightCommand[] PROGMEM = "LIGHT";
+PROGMEM_STRING(LightCommand, "LIGHT");
 
 static void _lightCommand(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
@@ -2727,7 +2727,7 @@ static void _lightCommand(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char LightCommandBrightness[] PROGMEM = "BRIGHTNESS";
+PROGMEM_STRING(LightCommandBrightness, "BRIGHTNESS");
 
 static void _lightCommandBrightness(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
@@ -2738,7 +2738,7 @@ static void _lightCommandBrightness(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char LightCommandChannel[] PROGMEM = "CHANNEL";
+PROGMEM_STRING(LightCommandChannel, "CHANNEL");
 
 static void _lightCommandChannel(::terminal::CommandContext&& ctx) {
     const size_t Channels { _light_channels.size() };
@@ -2776,7 +2776,7 @@ static void _lightCommandChannel(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char LightCommandRgb[] PROGMEM = "RGB";
+PROGMEM_STRING(LightCommandRgb, "RGB");
 
 static void _lightCommandColors(const ::terminal::CommandContext& ctx) {
     const auto rgb = _lightToTargetRgb();
@@ -2797,7 +2797,7 @@ static void _lightCommandRgb(::terminal::CommandContext&& ctx) {
     _lightCommandColors(ctx);
 }
 
-alignas(4) static constexpr char LightCommandHsv[] PROGMEM = "HSV";
+PROGMEM_STRING(LightCommandHsv, "HSV");
 
 static void _lightCommandHsv(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
@@ -2808,7 +2808,7 @@ static void _lightCommandHsv(::terminal::CommandContext&& ctx) {
     _lightCommandColors(ctx);
 }
 
-alignas(4) static constexpr char LightCommandKelvin[] PROGMEM = "KELVIN";
+PROGMEM_STRING(LightCommandKelvin, "KELVIN");
 
 static void _lightCommandKelvin(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
@@ -2821,7 +2821,7 @@ static void _lightCommandKelvin(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char LightCommandMired[] PROGMEM = "MIRED";
+PROGMEM_STRING(LightCommandMired, "MIRED");
 
 static void _lightCommandMired(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() > 1) {
diff --git a/code/espurna/lightfox.cpp b/code/espurna/lightfox.cpp
index dcd8614e..258d52c1 100644
--- a/code/espurna/lightfox.cpp
+++ b/code/espurna/lightfox.cpp
@@ -161,14 +161,14 @@ void _lightfoxWebSocketOnAction(uint32_t client_id, const char * action, JsonObj
 // -----------------------------------------------------------------------------
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char LightfoxCommandLearn[] PROGMEM = "LIGHTFOX.LEARN";
+PROGMEM_STRING(LightfoxCommandLearn, "LIGHTFOX.LEARN");
 
 static void _lightfoxCommandLearn(::terminal::CommandContext&& ctx) {
     lightfoxLearn();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char LightfoxCommandClear[] PROGMEM = "LIGHTFOX.LEARN";
+PROGMEM_STRING(LightfoxCommandClear, "LIGHTFOX.LEARN");
 
 static void _lightfoxCommandClear(::terminal::CommandContext&& ctx) {
     lightfoxClear();
diff --git a/code/espurna/main.cpp b/code/espurna/main.cpp
index 31c05bb2..4cb4312a 100644
--- a/code/espurna/main.cpp
+++ b/code/espurna/main.cpp
@@ -52,7 +52,7 @@ constexpr espurna::duration::Milliseconds loopDelay() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char LoopDelay[] PROGMEM = "loopDelay";
+PROGMEM_STRING(LoopDelay, "loopDelay");
 
 } // namespace keys
 
diff --git a/code/espurna/migrate.cpp b/code/espurna/migrate.cpp
index 055236d8..347d61c9 100644
--- a/code/espurna/migrate.cpp
+++ b/code/espurna/migrate.cpp
@@ -24,7 +24,7 @@ namespace schema {
 // Configuration version for the internal key-value storage
 // Represented as a 32bit int, updates every time things change
 constexpr static int Version PROGMEM { CFG_VERSION };
-alignas(4) static constexpr char Key[] PROGMEM = "cfg";
+PROGMEM_STRING(Key, "cfg");
 
 int version() {
     return getSetting(Key, Version);
diff --git a/code/espurna/mqtt.cpp b/code/espurna/mqtt.cpp
index 1f163f90..758b0de6 100644
--- a/code/espurna/mqtt.cpp
+++ b/code/espurna/mqtt.cpp
@@ -132,7 +132,7 @@ static constexpr espurna::duration::Milliseconds ReconnectStep { MQTT_RECONNECT_
 
 static constexpr size_t MessageLogMax { 128ul };
 
-alignas(4) static constexpr char Server[] PROGMEM = MQTT_SERVER;
+PROGMEM_STRING(Server, MQTT_SERVER);
 
 constexpr uint16_t port() {
     return MQTT_PORT;
@@ -146,12 +146,12 @@ constexpr bool autoconnect() {
     return 1 == MQTT_AUTOCONNECT;
 }
 
-alignas(4) static constexpr char Topic[] PROGMEM = MQTT_TOPIC;
-alignas(4) static constexpr char Getter[] PROGMEM = MQTT_GETTER;
-alignas(4) static constexpr char Setter[] PROGMEM = MQTT_SETTER;
+PROGMEM_STRING(Topic, MQTT_TOPIC);
+PROGMEM_STRING(Getter, MQTT_GETTER);
+PROGMEM_STRING(Setter, MQTT_SETTER);
 
-alignas(4) static constexpr char User[] PROGMEM = MQTT_USER;
-alignas(4) static constexpr char Password[] PROGMEM = MQTT_PASS;
+PROGMEM_STRING(User, MQTT_USER);
+PROGMEM_STRING(Password, MQTT_PASS);
 
 constexpr int qos() {
     return MQTT_QOS;
@@ -171,21 +171,21 @@ constexpr KeepAlive keepalive() {
 static_assert(keepalive() >= KeepaliveMin, "");
 static_assert(keepalive() <= KeepaliveMax, "");
 
-alignas(4) static constexpr char TopicWill[] PROGMEM = MQTT_TOPIC_STATUS;
+PROGMEM_STRING(TopicWill, MQTT_TOPIC_STATUS);
 
 constexpr bool json() {
     return 1 == MQTT_USE_JSON;
 }
 
 static constexpr auto JsonDelay = espurna::duration::Milliseconds(MQTT_USE_JSON_DELAY);
-alignas(4) static constexpr char TopicJson[] PROGMEM = MQTT_TOPIC_JSON;
+PROGMEM_STRING(TopicJson, MQTT_TOPIC_JSON);
 
 constexpr espurna::duration::Milliseconds skipTime() {
     return espurna::duration::Milliseconds(MQTT_SKIP_TIME);
 }
 
-alignas(4) static constexpr char PayloadOnline[] PROGMEM = MQTT_STATUS_ONLINE;
-alignas(4) static constexpr char PayloadOffline[] PROGMEM = MQTT_STATUS_OFFLINE;
+PROGMEM_STRING(PayloadOnline, MQTT_STATUS_ONLINE);
+PROGMEM_STRING(PayloadOffline, MQTT_STATUS_OFFLINE);
 
 constexpr bool secure() {
     return 1 == MQTT_SSL_ENABLED;
@@ -195,7 +195,7 @@ int secureClientCheck() {
     return MQTT_SECURE_CLIENT_CHECK;
 }
 
-alignas(4) static constexpr char Fingerprint[] PROGMEM = MQTT_SSL_FINGERPRINT;
+PROGMEM_STRING(Fingerprint, MQTT_SSL_FINGERPRINT);
 
 constexpr uint16_t mfln() {
     return MQTT_SECURE_CLIENT_MFLN;
@@ -208,38 +208,38 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Server[] PROGMEM = "mqttServer";
-alignas(4) static constexpr char Port[] PROGMEM = "mqttPort";
+PROGMEM_STRING(Server, "mqttServer");
+PROGMEM_STRING(Port, "mqttPort");
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "mqttEnabled";
-alignas(4) static constexpr char Autoconnect[] PROGMEM = "mqttAutoconnect";
+PROGMEM_STRING(Enabled, "mqttEnabled");
+PROGMEM_STRING(Autoconnect, "mqttAutoconnect");
 
-alignas(4) static constexpr char Topic[] PROGMEM = "mqttTopic";
-alignas(4) static constexpr char Getter[] PROGMEM = "mqttGetter";
-alignas(4) static constexpr char Setter[] PROGMEM = "mqttSetter";
+PROGMEM_STRING(Topic, "mqttTopic");
+PROGMEM_STRING(Getter, "mqttGetter");
+PROGMEM_STRING(Setter, "mqttSetter");
 
-alignas(4) static constexpr char User[] PROGMEM = "mqttUser";
-alignas(4) static constexpr char Password[] PROGMEM = "mqttPassword";
-alignas(4) static constexpr char QoS[] PROGMEM = "mqttQoS";
-alignas(4) static constexpr char Retain[] PROGMEM = "mqttRetain";
-alignas(4) static constexpr char Keepalive[] PROGMEM = "mqttKeep";
-alignas(4) static constexpr char ClientId[] PROGMEM = "mqttClientID";
-alignas(4) static constexpr char TopicWill[] PROGMEM = "mqttWill";
+PROGMEM_STRING(User, "mqttUser");
+PROGMEM_STRING(Password, "mqttPassword");
+PROGMEM_STRING(QoS, "mqttQoS");
+PROGMEM_STRING(Retain, "mqttRetain");
+PROGMEM_STRING(Keepalive, "mqttKeep");
+PROGMEM_STRING(ClientId, "mqttClientID");
+PROGMEM_STRING(TopicWill, "mqttWill");
 
-alignas(4) static constexpr char UseJson[] PROGMEM = "mqttUseJson";
-alignas(4) static constexpr char TopicJson[] PROGMEM = "mqttJson";
+PROGMEM_STRING(UseJson, "mqttUseJson");
+PROGMEM_STRING(TopicJson, "mqttJson");
 
-alignas(4) static constexpr char HeartbeatMode[] PROGMEM = "mqttHbMode";
-alignas(4) static constexpr char HeartbeatInterval[] PROGMEM = "mqttHbIntvl";
-alignas(4) static constexpr char SkipTime[] PROGMEM = "mqttSkipTime";
+PROGMEM_STRING(HeartbeatMode, "mqttHbMode");
+PROGMEM_STRING(HeartbeatInterval, "mqttHbIntvl");
+PROGMEM_STRING(SkipTime, "mqttSkipTime");
 
-alignas(4) static constexpr char PayloadOnline[] PROGMEM = "mqttPayloadOnline";
-alignas(4) static constexpr char PayloadOffline[] PROGMEM = "mqttPayloadOffline";
+PROGMEM_STRING(PayloadOnline, "mqttPayloadOnline");
+PROGMEM_STRING(PayloadOffline, "mqttPayloadOffline");
 
-alignas(4) static constexpr char Secure[] PROGMEM = "mqttUseSSL";
-alignas(4) static constexpr char Fingerprint[] PROGMEM = "mqttFP";
-alignas(4) static constexpr char SecureClientCheck[] PROGMEM = "mqttScCheck";
-alignas(4) static constexpr char SecureClientMfln[] PROGMEM = "mqttScMFLN";
+PROGMEM_STRING(Secure, "mqttUseSSL");
+PROGMEM_STRING(Fingerprint, "mqttFP");
+PROGMEM_STRING(SecureClientCheck, "mqttScCheck");
+PROGMEM_STRING(SecureClientMfln, "mqttScMFLN");
 
 } // namespace
 } // namespace keys
@@ -842,7 +842,7 @@ void _mqttBackwards() {
 const char* _mqttBuildInfo() {
 #define __MQTT_INFO_STR(X) #X
 #define _MQTT_INFO_STR(X) __MQTT_INFO_STR(X)
-    alignas(4) static constexpr char out[] PROGMEM {
+    alignas(4) static constexpr char out[] PROGMEM_STRING_ATTR {
 #if MQTT_LIBRARY == MQTT_LIBRARY_ASYNCMQTTCLIENT
         "AsyncMqttClient"
 #elif MQTT_LIBRARY == MQTT_LIBRARY_ARDUINOMQTT
@@ -958,7 +958,7 @@ void _mqttWebSocketOnConnected(JsonObject& root) {
 #if TERMINAL_SUPPORT
 namespace {
 
-alignas(4) static constexpr char MqttCommand[] PROGMEM = "MQTT";
+PROGMEM_STRING(MqttCommand, "MQTT");
 
 static void _mqttCommand(::terminal::CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("%s\n"), _mqttBuildInfo());
@@ -967,7 +967,7 @@ static void _mqttCommand(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char MqttCommandReset[] PROGMEM = "MQTT.RESET";
+PROGMEM_STRING(MqttCommandReset, "MQTT.RESET");
 
 static void _mqttCommandReset(::terminal::CommandContext&& ctx) {
     _mqttConfigure();
@@ -975,7 +975,7 @@ static void _mqttCommandReset(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char MqttCommandSend[] PROGMEM = "MQTT.SEND";
+PROGMEM_STRING(MqttCommandSend, "MQTT.SEND");
 
 static void _mqttCommandSend(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 3) {
diff --git a/code/espurna/network.cpp b/code/espurna/network.cpp
index 118b6130..16f05f48 100644
--- a/code/espurna/network.cpp
+++ b/code/espurna/network.cpp
@@ -103,7 +103,7 @@ void start(String hostname, IpFoundCallback callback) {
 namespace terminal {
 namespace commands {
 
-alignas(4) static constexpr char Host[] PROGMEM = "HOST";
+PROGMEM_STRING(Host, "HOST");
 
 void host(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
@@ -127,7 +127,7 @@ void host(::terminal::CommandContext&& ctx) {
     }
 }
 
-alignas(4) static constexpr char Netstat[] PROGMEM = "NETSTAT";
+PROGMEM_STRING(Netstat, "NETSTAT");
 
 void netstat(::terminal::CommandContext&& ctx) {
     const struct tcp_pcb* pcbs[] {
@@ -149,7 +149,7 @@ void netstat(::terminal::CommandContext&& ctx) {
 }
 
 #if SECURE_CLIENT == SECURE_CLIENT_BEARSSL
-alignas(4) static constexpr char MflnProbe[] PROGMEM = "MFLN.PROBE";
+PROGMEM_STRING(MflnProbe, "MFLN.PROBE");
 
 void mfln_probe(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 3) {
diff --git a/code/espurna/nofuss.cpp b/code/espurna/nofuss.cpp
index 8c9b3404..476a2abc 100644
--- a/code/espurna/nofuss.cpp
+++ b/code/espurna/nofuss.cpp
@@ -98,7 +98,7 @@ void _nofussLoop() {
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char NofussCommand[] PROGMEM = "NOFUSS";
+PROGMEM_STRING(NofussCommand, "NOFUSS");
 
 static void _nofussCommand(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
diff --git a/code/espurna/ntp.cpp b/code/espurna/ntp.cpp
index 432008df..bdf16748 100644
--- a/code/espurna/ntp.cpp
+++ b/code/espurna/ntp.cpp
@@ -487,7 +487,7 @@ void report(Print& out) {
 
 namespace commands {
 
-alignas(4) static constexpr char Ntp[] PROGMEM = "NTP";
+PROGMEM_STRING(Ntp, "NTP");
 
 void ntp(::terminal::CommandContext&& ctx) {
     if (synced()) {
@@ -499,7 +499,7 @@ void ntp(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("NTP not synced"));
 }
 
-alignas(4) static constexpr char Sync[] PROGMEM = "NTP.SYNC";
+PROGMEM_STRING(Sync, "NTP.SYNC");
 
 void sync(::terminal::CommandContext&& ctx) {
     if (synced()) {
@@ -512,7 +512,7 @@ void sync(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("NTP waiting for initial sync"));
 }
 
-alignas(4) static constexpr char Set[] PROGMEM = "NTP.SET";
+PROGMEM_STRING(Set, "NTP.SET");
 
 [[gnu::unused]]
 void set_simple(::terminal::CommandContext&& ctx) {
diff --git a/code/espurna/ota_asynctcp.cpp b/code/espurna/ota_asynctcp.cpp
index 9f594ae6..6b591bb0 100644
--- a/code/espurna/ota_asynctcp.cpp
+++ b/code/espurna/ota_asynctcp.cpp
@@ -243,7 +243,7 @@ void clientFromUrl(StringView payload) {
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char OtaCommand[] PROGMEM = "OTA";
+PROGMEM_STRING(OtaCommand, "OTA");
 
 static void otaCommand(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
diff --git a/code/espurna/ota_httpupdate.cpp b/code/espurna/ota_httpupdate.cpp
index 4e551b1e..cca26992 100644
--- a/code/espurna/ota_httpupdate.cpp
+++ b/code/espurna/ota_httpupdate.cpp
@@ -159,7 +159,7 @@ void clientQueueUrl(espurna::StringView url) {
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char OtaCommand[] PROGMEM = "OTA";
+PROGMEM_STRING(OtaCommand, "OTA");
 
 static void otaCommand(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
diff --git a/code/espurna/pwm.cpp b/code/espurna/pwm.cpp
index b9ea2f03..37422183 100644
--- a/code/espurna/pwm.cpp
+++ b/code/espurna/pwm.cpp
@@ -48,9 +48,9 @@ constexpr float limit() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Frequency[] PROGMEM = "pwmFreq";
-alignas(4) static constexpr char Resolution[] PROGMEM = "pwmRes";
-alignas(4) static constexpr char Limit[] PROGMEM = "pwmLimit";
+PROGMEM_STRING(Frequency, "pwmFreq");
+PROGMEM_STRING(Resolution, "pwmRes");
+PROGMEM_STRING(Limit, "pwmLimit");
 
 } // namespace keys
 
@@ -437,7 +437,7 @@ using namespace generic;
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char PwmWrite[] PROGMEM = "PWM.WRITE";
+PROGMEM_STRING(PwmWrite, "PWM.WRITE");
 
 void pwm_write(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 3) {
diff --git a/code/espurna/relay.cpp b/code/espurna/relay.cpp
index 5da3171f..fe907667 100644
--- a/code/espurna/relay.cpp
+++ b/code/espurna/relay.cpp
@@ -57,8 +57,8 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Time[] PROGMEM = "relayFloodTime";
-alignas(4) static constexpr char Changes[] PROGMEM = "relayFloodChanges";
+PROGMEM_STRING(Time, "relayFloodTime");
+PROGMEM_STRING(Changes, "relayFloodChanges");
 
 } // namespace
 } // namespace keys
@@ -217,9 +217,9 @@ constexpr RelayMqttTopicMode mqttTopicMode(size_t index) {
     );
 }
 
-alignas(4) static constexpr char PayloadOn[] PROGMEM = RELAY_MQTT_ON;
-alignas(4) static constexpr char PayloadOff[] PROGMEM = RELAY_MQTT_OFF;
-alignas(4) static constexpr char PayloadToggle[] PROGMEM = RELAY_MQTT_TOGGLE;
+PROGMEM_STRING(PayloadOn, RELAY_MQTT_ON);
+PROGMEM_STRING(PayloadOff, RELAY_MQTT_OFF);
+PROGMEM_STRING(PayloadToggle, RELAY_MQTT_TOGGLE);
 
 const StringView mqttTopicSub(size_t index) {
     return (
@@ -328,8 +328,8 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Time[] PROGMEM = "relayTime";
-alignas(4) static constexpr char Mode[] PROGMEM = "relayPulse";
+PROGMEM_STRING(Time, "relayTime");
+PROGMEM_STRING(Mode, "relayPulse");
 
 } // namespace
 } // namespace keys
@@ -517,9 +517,9 @@ namespace {
 
 using espurna::settings::options::Enumeration;
 
-alignas(4) static constexpr char TristateNone[] PROGMEM = "none";
-alignas(4) static constexpr char TristateOff[] PROGMEM = "off";
-alignas(4) static constexpr char TristateOn[] PROGMEM = "on";
+PROGMEM_STRING(TristateNone, "none");
+PROGMEM_STRING(TristateOff, "off");
+PROGMEM_STRING(TristateOn, "on");
 
 template <typename T>
 struct RelayTristateHelper {
@@ -541,10 +541,10 @@ struct RelayTristateHelper {
 template <typename T>
 constexpr std::array<Enumeration<T>, 3> RelayTristateHelper<T>::Options;
 
-alignas(4) static constexpr char PayloadStatusOff[] PROGMEM = "off";
-alignas(4) static constexpr char PayloadStatusOn[] PROGMEM = "on";
-alignas(4) static constexpr char PayloadStatusToggle[] PROGMEM = "toggle";
-alignas(4) static constexpr char PayloadStatusUnknown[] PROGMEM = "unknown";
+PROGMEM_STRING(PayloadStatusOff, "off");
+PROGMEM_STRING(PayloadStatusOn, "on");
+PROGMEM_STRING(PayloadStatusToggle, "toggle");
+PROGMEM_STRING(PayloadStatusUnknown, "unknown");
 
 static constexpr std::array<Enumeration<PayloadStatus>, 4> PayloadStatusOptions PROGMEM {
     {{PayloadStatus::Off, PayloadStatusOff},
@@ -553,20 +553,20 @@ static constexpr std::array<Enumeration<PayloadStatus>, 4> PayloadStatusOptions
      {PayloadStatus::Unknown, PayloadStatusUnknown}}
 };
 
-alignas(4) static constexpr char Normal[] PROGMEM = "normal";
-alignas(4) static constexpr char Inverse[] PROGMEM = "inverse";
+PROGMEM_STRING(Normal, "normal");
+PROGMEM_STRING(Inverse, "inverse");
 
 static constexpr std::array<Enumeration<RelayMqttTopicMode>, 2> RelayMqttTopicModeOptions PROGMEM {
     {{RelayMqttTopicMode::Normal, Normal},
      {RelayMqttTopicMode::Inverse, Inverse}}
 };
 
-alignas(4) static constexpr char RelayBootOff[] PROGMEM = "off";
-alignas(4) static constexpr char RelayBootOn[] PROGMEM = "on";
-alignas(4) static constexpr char RelayBootSame[] PROGMEM = "same";
-alignas(4) static constexpr char RelayBootToggle[] PROGMEM = "toggle";
-alignas(4) static constexpr char RelayBootLockedOff[] PROGMEM = "locked-off";
-alignas(4) static constexpr char RelayBootLockedOn[] PROGMEM = "locked-on";
+PROGMEM_STRING(RelayBootOff, "off");
+PROGMEM_STRING(RelayBootOn, "on");
+PROGMEM_STRING(RelayBootSame, "same");
+PROGMEM_STRING(RelayBootToggle, "toggle");
+PROGMEM_STRING(RelayBootLockedOff, "locked-off");
+PROGMEM_STRING(RelayBootLockedOn, "locked-on");
 
 static constexpr std::array<Enumeration<RelayBoot>, 6> RelayBootOptions PROGMEM {
     {{RelayBoot::Off, RelayBootOff},
@@ -577,11 +577,11 @@ static constexpr std::array<Enumeration<RelayBoot>, 6> RelayBootOptions PROGMEM
      {RelayBoot::LockedOn, RelayBootLockedOn}}
 };
 
-alignas(4) static constexpr char RelayProviderNone[] PROGMEM = "none";
-alignas(4) static constexpr char RelayProviderDummy[] PROGMEM = "dummy";
-alignas(4) static constexpr char RelayProviderGpio[] PROGMEM = "gpio";
-alignas(4) static constexpr char RelayProviderDual[] PROGMEM = "dual";
-alignas(4) static constexpr char RelayProviderStm[] PROGMEM = "stm";
+PROGMEM_STRING(RelayProviderNone, "none");
+PROGMEM_STRING(RelayProviderDummy, "dummy");
+PROGMEM_STRING(RelayProviderGpio, "gpio");
+PROGMEM_STRING(RelayProviderDual, "dual");
+PROGMEM_STRING(RelayProviderStm, "stm");
 
 static constexpr std::array<Enumeration<RelayProvider>, 5> RelayProviderOptions PROGMEM {
     {{RelayProvider::None, RelayProviderNone},
@@ -591,10 +591,10 @@ static constexpr std::array<Enumeration<RelayProvider>, 5> RelayProviderOptions
      {RelayProvider::Stm, RelayProviderStm}}
 };
 
-alignas(4) constexpr static char RelayTypeNormal[] PROGMEM = "normal";
-alignas(4) constexpr static char RelayTypeInverse[] PROGMEM = "inverse";
-alignas(4) constexpr static char RelayTypeLatched[] PROGMEM = "latched";
-alignas(4) constexpr static char RelayTypeLatchedInverse[] PROGMEM = "latched-inverse";
+PROGMEM_STRING(RelayTypeNormal, "normal");
+PROGMEM_STRING(RelayTypeInverse, "inverse");
+PROGMEM_STRING(RelayTypeLatched, "latched");
+PROGMEM_STRING(RelayTypeLatchedInverse, "latched-inverse");
 
 static constexpr std::array<Enumeration<RelayType>, 4> RelayTypeOptions PROGMEM {
     {{RelayType::Normal, RelayTypeNormal},
@@ -603,11 +603,11 @@ static constexpr std::array<Enumeration<RelayType>, 4> RelayTypeOptions PROGMEM
      {RelayType::LatchedInverse, RelayTypeLatchedInverse}}
 };
 
-alignas(4) constexpr static char None[] PROGMEM = "none";
-alignas(4) constexpr static char ZeroOrOne[] PROGMEM = "zero-or-one";
-alignas(4) constexpr static char JustOne[] PROGMEM = "just-one";
-alignas(4) constexpr static char All[] PROGMEM = "all";
-alignas(4) constexpr static char First[] PROGMEM = "first";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(ZeroOrOne, "zero-or-one");
+PROGMEM_STRING(JustOne, "just-one");
+PROGMEM_STRING(All, "all");
+PROGMEM_STRING(First, "first");
 
 static constexpr std::array<Enumeration<RelaySync>, 5> RelaySyncOptions PROGMEM {
     {{RelaySync::None, None},
@@ -769,31 +769,31 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Name[] PROGMEM = "relayName";
-alignas(4) static constexpr char Provider[] PROGMEM = "relayProv";
-alignas(4) static constexpr char Type[] PROGMEM = "relayType";
-alignas(4) static constexpr char GpioType[] PROGMEM = "relayGpioType";
-alignas(4) static constexpr char Gpio[] PROGMEM = "relayGpio";
-alignas(4) static constexpr char ResetGpio[] PROGMEM = "relayResetGpio";
-alignas(4) static constexpr char Boot[] PROGMEM = "relayBoot";
-alignas(4) static constexpr char DelayOn[] PROGMEM = "relayDelayOn";
-alignas(4) static constexpr char DelayOff[] PROGMEM = "relayDelayOff";
+PROGMEM_STRING(Name, "relayName");
+PROGMEM_STRING(Provider, "relayProv");
+PROGMEM_STRING(Type, "relayType");
+PROGMEM_STRING(GpioType, "relayGpioType");
+PROGMEM_STRING(Gpio, "relayGpio");
+PROGMEM_STRING(ResetGpio, "relayResetGpio");
+PROGMEM_STRING(Boot, "relayBoot");
+PROGMEM_STRING(DelayOn, "relayDelayOn");
+PROGMEM_STRING(DelayOff, "relayDelayOff");
 
 #if MQTT_SUPPORT
-alignas(4) static constexpr char TopicPub[] PROGMEM = "relayTopicPub";
-alignas(4) static constexpr char TopicSub[] PROGMEM = "relayTopicSub";
-alignas(4) static constexpr char TopicMode[] PROGMEM = "relayTopicMode";
-alignas(4) static constexpr char MqttDisconnection[] PROGMEM = "relayMqttDisc";
+PROGMEM_STRING(TopicPub, "relayTopicPub");
+PROGMEM_STRING(TopicSub, "relayTopicSub");
+PROGMEM_STRING(TopicMode, "relayTopicMode");
+PROGMEM_STRING(MqttDisconnection, "relayMqttDisc");
 #endif
 
-alignas(4) static constexpr char Dummy[] PROGMEM = "relayDummy";
-alignas(4) static constexpr char BootMask[] PROGMEM = "relayBootMask";
-alignas(4) static constexpr char Interlock[] PROGMEM = "relayIlkDelay";
-alignas(4) static constexpr char Sync[] PROGMEM = "relaySync";
+PROGMEM_STRING(Dummy, "relayDummy");
+PROGMEM_STRING(BootMask, "relayBootMask");
+PROGMEM_STRING(Interlock, "relayIlkDelay");
+PROGMEM_STRING(Sync, "relaySync");
 
-alignas(4) static constexpr char PayloadOn[] PROGMEM = "relayPayloadOn";
-alignas(4) static constexpr char PayloadOff[] PROGMEM = "relayPayloadOff";
-alignas(4) static constexpr char PayloadToggle[] PROGMEM = "relayPayloadOff";
+PROGMEM_STRING(PayloadOn, "relayPayloadOn");
+PROGMEM_STRING(PayloadOff, "relayPayloadOff");
+PROGMEM_STRING(PayloadToggle, "relayPayloadOff");
 
 } // namespace
 } // namespace keys
@@ -2561,7 +2561,7 @@ void _relayPrint(Print& out, size_t start, size_t stop) {
     }
 }
 
-alignas(4) static constexpr char RelayCommand[] PROGMEM = "RELAY";
+PROGMEM_STRING(RelayCommand, "RELAY");
 
 static void _relayCommand(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 1) {
@@ -2595,7 +2595,7 @@ static void _relayCommand(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char PulseCommand[] PROGMEM = "PULSE";
+PROGMEM_STRING(PulseCommand, "PULSE");
 
 static void _relayCommandPulse(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() < 3) {
@@ -2860,7 +2860,7 @@ namespace query {
 namespace {
 
 bool checkSamePrefix(StringView key) {
-    alignas(4) static constexpr char Prefix[] PROGMEM = "relay";
+    PROGMEM_STRING(Prefix, "relay");
     return espurna::settings::query::samePrefix(key, Prefix);
 }
 
diff --git a/code/espurna/rfbridge.cpp b/code/espurna/rfbridge.cpp
index c378d4de..34aa7f59 100644
--- a/code/espurna/rfbridge.cpp
+++ b/code/espurna/rfbridge.cpp
@@ -338,8 +338,8 @@ namespace rfbridge {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char On[] PROGMEM = "rfbON";
-alignas(4) static constexpr char Off[] PROGMEM = "rfbOFF";
+PROGMEM_STRING(On, "rfbON");
+PROGMEM_STRING(Off, "rfbOFF");
 
 } // namespace keys
 
@@ -1174,7 +1174,7 @@ void _rfbCommandStatusDispatch(::terminal::CommandContext&& ctx, size_t id, Rela
     }
 }
 
-alignas(4) static constexpr char RfbCommandSend[] PROGMEM = "RFB.SEND";
+PROGMEM_STRING(RfbCommandSend, "RFB.SEND");
 
 static void _rfbCommandSend(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 2) {
@@ -1186,7 +1186,7 @@ static void _rfbCommandSend(::terminal::CommandContext&& ctx) {
 }
 
 #if RELAY_SUPPORT
-alignas(4) static constexpr char RfbCommandLearn[] PROGMEM = "RFB.LEARN";
+PROGMEM_STRING(RfbCommandLearn, "RFB.LEARN");
 
 static void _rfbCommandLearn(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 3) {
@@ -1203,7 +1203,7 @@ static void _rfbCommandLearn(::terminal::CommandContext&& ctx) {
     _rfbCommandStatusDispatch(std::move(ctx), id, rfbLearn);
 }
 
-alignas(4) static constexpr char RfbCommandForget[] PROGMEM = "RFB.FORGET";
+PROGMEM_STRING(RfbCommandForget, "RFB.FORGET");
 
 static void _rfbCommandForget(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() < 2) {
@@ -1230,7 +1230,7 @@ static void _rfbCommandForget(::terminal::CommandContext&& ctx) {
 #endif // if RELAY_SUPPORT
 
 #if RFB_PROVIDER == RFB_PROVIDER_EFM8BB1
-alignas(4) static constexpr char RfbCommandWrite[] PROGMEM = "RFB.WRITE";
+PROGMEM_STRING(RfbCommandWrite, "RFB.WRITE");
 
 static void _rfbCommandWrite(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
diff --git a/code/espurna/rpc.cpp b/code/espurna/rpc.cpp
index 34007eb9..87d21341 100644
--- a/code/espurna/rpc.cpp
+++ b/code/espurna/rpc.cpp
@@ -18,12 +18,12 @@ namespace espurna {
 namespace rpc {
 namespace {
 
-alignas(4) static constexpr char Reboot[] PROGMEM = "reboot";
-alignas(4) static constexpr char Heartbeat[] PROGMEM = "heartbeat";
+PROGMEM_STRING(Reboot, "reboot");
+PROGMEM_STRING(Heartbeat, "heartbeat");
 
-alignas(4) static constexpr char On[] PROGMEM = "on";
-alignas(4) static constexpr char Off[] PROGMEM = "off";
-alignas(4) static constexpr char Toggle[] PROGMEM = "toggle";
+PROGMEM_STRING(On, "on");
+PROGMEM_STRING(Off, "off");
+PROGMEM_STRING(Toggle, "toggle");
 
 void rpcPrepareReset() {
     prepareReset(CustomResetReason::Rpc);
diff --git a/code/espurna/rpnrules.cpp b/code/espurna/rpnrules.cpp
index 26f394a7..92da5b36 100644
--- a/code/espurna/rpnrules.cpp
+++ b/code/espurna/rpnrules.cpp
@@ -111,12 +111,12 @@ constexpr unsigned long delay() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Sticky[] PROGMEM = "rpnSticky";
-alignas(4) static constexpr char Delay[] PROGMEM = "rpnDelay";
-alignas(4) static constexpr char Rule[] PROGMEM = "rpnRule";
+PROGMEM_STRING(Sticky, "rpnSticky");
+PROGMEM_STRING(Delay, "rpnDelay");
+PROGMEM_STRING(Rule, "rpnRule");
 
-alignas(4) static constexpr char Topic[] PROGMEM = "rpnTopic";
-alignas(4) static constexpr char Name[] PROGMEM = "rpnName";
+PROGMEM_STRING(Topic, "rpnTopic");
+PROGMEM_STRING(Name, "rpnName");
 
 } // namespace keys
 
@@ -288,7 +288,7 @@ void showStack(Print& output) {
     output.print(F("      (empty)\n"));
 }
 
-alignas(4) static constexpr char Runners[] PROGMEM = "RPN.RUNNERS";
+PROGMEM_STRING(Runners, "RPN.RUNNERS");
 
 void runners(::terminal::CommandContext&& ctx) {
     if (internal::runners.empty()) {
@@ -311,7 +311,7 @@ void runners(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Variables[] PROGMEM = "RPN.VARS";
+PROGMEM_STRING(Variables, "RPN.VARS");
 
 void variables(::terminal::CommandContext&& ctx) {
     rpn_variables_foreach(internal::context,
@@ -325,7 +325,7 @@ void variables(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Operators[] PROGMEM = "RPN.OPS";
+PROGMEM_STRING(Operators, "RPN.OPS");
 
 void operators(::terminal::CommandContext&& ctx) {
     rpn_operators_foreach(internal::context,
@@ -339,7 +339,7 @@ void operators(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Test[] PROGMEM = "RPN.TEST";
+PROGMEM_STRING(Test, "RPN.TEST");
 
 void test(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
@@ -853,9 +853,9 @@ constexpr uint32_t StaleDelay { 10000ul };
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char RepeatWindow[] PROGMEM = "rfbRepeatWindow";
-alignas(4) static constexpr char MatchWindow[] PROGMEM = "rfbWatchWindow";
-alignas(4) static constexpr char StaleDelay[] PROGMEM = "rfbStaleDelay";
+PROGMEM_STRING(RepeatWindow, "rfbRepeatWindow");
+PROGMEM_STRING(MatchWindow, "rfbWatchWindow");
+PROGMEM_STRING(StaleDelay, "rfbStaleDelay");
 
 } // namespace keys
 
@@ -1048,7 +1048,7 @@ void codeHandler(unsigned char protocol, const char* raw_code) {
     schedule();
 }
 
-alignas(4) static constexpr char RfbCodes[] PROGMEM = "RFB.CODES";
+PROGMEM_STRING(RfbCodes, "RFB.CODES");
 
 void rfb_codes(::terminal::CommandContext&& ctx) {
     for (auto& code : internal::codes) {
diff --git a/code/espurna/rtcmem.cpp b/code/espurna/rtcmem.cpp
index 25d74066..87225ef3 100644
--- a/code/espurna/rtcmem.cpp
+++ b/code/espurna/rtcmem.cpp
@@ -66,14 +66,14 @@ bool status() {
 #if TERMINAL_SUPPORT
 namespace terminal {
 
-alignas(4) static constexpr char Init[] PROGMEM = "RTCMEM.INIT";
+PROGMEM_STRING(Init, "RTCMEM.INIT");
 
 void init(::terminal::CommandContext&& ctx) {
     rtc::init();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Dump[] PROGMEM = "RTCMEM.DUMP";
+PROGMEM_STRING(Dump, "RTCMEM.DUMP");
 
 void dump(::terminal::CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("boot_status=%s status=%s capacity=%u\n"),
diff --git a/code/espurna/scheduler.cpp b/code/espurna/scheduler.cpp
index ea829af5..d2c3ee23 100644
--- a/code/espurna/scheduler.cpp
+++ b/code/espurna/scheduler.cpp
@@ -112,10 +112,10 @@ namespace settings {
 namespace options {
 namespace {
 
-alignas(4) static constexpr char None[] PROGMEM = "none";
-alignas(4) static constexpr char Relay[] PROGMEM = "relay";
-alignas(4) static constexpr char Channel[] PROGMEM = "channel";
-alignas(4) static constexpr char Curtain[] PROGMEM = "curtain";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(Relay, "relay");
+PROGMEM_STRING(Channel, "channel");
+PROGMEM_STRING(Curtain, "curtain");
 
 static constexpr std::array<Enumeration<scheduler::Type>, 4> SchedulerTypeOptions PROGMEM {
     {{scheduler::Type::None, None},
@@ -262,15 +262,15 @@ namespace settings {
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "schEnabled";
-alignas(4) static constexpr char Target[] PROGMEM = "schTarget";
-alignas(4) static constexpr char Type[] PROGMEM = "schType";
-alignas(4) static constexpr char Action[] PROGMEM = "schAction";
-alignas(4) static constexpr char Restore[] PROGMEM = "schRestore";
-alignas(4) static constexpr char UseUTC[] PROGMEM = "schUTC";
-alignas(4) static constexpr char Weekdays[] PROGMEM = "schWDs";
-alignas(4) static constexpr char Hour[] PROGMEM = "schHour";
-alignas(4) static constexpr char Minute[] PROGMEM = "schMinute";
+PROGMEM_STRING(Enabled, "schEnabled");
+PROGMEM_STRING(Target, "schTarget");
+PROGMEM_STRING(Type, "schType");
+PROGMEM_STRING(Action, "schAction");
+PROGMEM_STRING(Restore, "schRestore");
+PROGMEM_STRING(UseUTC, "schUTC");
+PROGMEM_STRING(Weekdays, "schWDs");
+PROGMEM_STRING(Hour, "schHour");
+PROGMEM_STRING(Minute, "schMinute");
 
 } // namespace
 } // namespace keys
@@ -414,7 +414,7 @@ void migrate(int version) {
 namespace query {
 
 bool checkSamePrefix(StringView key) {
-    alignas(4) static constexpr char Prefix[] PROGMEM = "sch";
+    PROGMEM_STRING(Prefix, "sch");
     return espurna::settings::query::samePrefix(key, Prefix);
 }
 
@@ -438,15 +438,15 @@ void setup() {
 namespace api {
 namespace keys {
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "enabled";
-alignas(4) static constexpr char Target[] PROGMEM = "enabled";
-alignas(4) static constexpr char Type[] PROGMEM = "type";
-alignas(4) static constexpr char Action[] PROGMEM = "action";
-alignas(4) static constexpr char Restore[] PROGMEM = "restore";
-alignas(4) static constexpr char UseUTC[] PROGMEM = "utc";
-alignas(4) static constexpr char Weekdays[] PROGMEM = "weekdays";
-alignas(4) static constexpr char Hour[] PROGMEM = "hour";
-alignas(4) static constexpr char Minute[] PROGMEM = "minute";
+PROGMEM_STRING(Enabled, "enabled");
+PROGMEM_STRING(Target, "enabled");
+PROGMEM_STRING(Type, "type");
+PROGMEM_STRING(Action, "action");
+PROGMEM_STRING(Restore, "restore");
+PROGMEM_STRING(UseUTC, "utc");
+PROGMEM_STRING(Weekdays, "weekdays");
+PROGMEM_STRING(Hour, "hour");
+PROGMEM_STRING(Minute, "minute");
 
 } // namespace keys
 
diff --git a/code/espurna/sensor.cpp b/code/espurna/sensor.cpp
index 12bb4e08..93bf7668 100644
--- a/code/espurna/sensor.cpp
+++ b/code/espurna/sensor.cpp
@@ -891,11 +891,11 @@ namespace settings {
 namespace filters {
 namespace {
 
-alignas(4) static constexpr char Last[] PROGMEM = "last";
-alignas(4) static constexpr char Max[] PROGMEM = "max";
-alignas(4) static constexpr char Median[] PROGMEM = "median";
-alignas(4) static constexpr char MovingAverage[] PROGMEM = "moving-average";
-alignas(4) static constexpr char Sum[] PROGMEM = "sum";
+PROGMEM_STRING(Last, "last");
+PROGMEM_STRING(Max, "max");
+PROGMEM_STRING(Median, "median");
+PROGMEM_STRING(MovingAverage, "moving-average");
+PROGMEM_STRING(Sum, "sum");
 
 static constexpr espurna::settings::options::Enumeration<Filter> Options[] PROGMEM {
     {Filter::Last, Last},
@@ -911,33 +911,33 @@ static constexpr espurna::settings::options::Enumeration<Filter> Options[] PROGM
 namespace units {
 namespace {
 
-alignas(4) static constexpr char Farenheit[] PROGMEM = "°F";
-alignas(4) static constexpr char Celcius[] PROGMEM = "°C";
-alignas(4) static constexpr char Kelvin[] PROGMEM = "K";
-alignas(4) static constexpr char Percentage[] PROGMEM = "%";
-alignas(4) static constexpr char Hectopascal[] PROGMEM = "hPa";
-alignas(4) static constexpr char Ampere[] PROGMEM = "A";
-alignas(4) static constexpr char Volt[] PROGMEM = "V";
-alignas(4) static constexpr char Watt[] PROGMEM = "W";
-alignas(4) static constexpr char Kilowatt[] PROGMEM = "kW";
-alignas(4) static constexpr char Voltampere[] PROGMEM = "VA";
-alignas(4) static constexpr char Kilovoltampere[] PROGMEM = "kVA";
-alignas(4) static constexpr char VoltampereReactive[] PROGMEM = "VAR";
-alignas(4) static constexpr char KilovoltampereReactive[] PROGMEM = "kVAR";
-alignas(4) static constexpr char Joule[] PROGMEM = "J";
-alignas(4) static constexpr char KilowattHour[] PROGMEM = "kWh";
-alignas(4) static constexpr char MicrogrammPerCubicMeter[] PROGMEM = "µg/m³";
-alignas(4) static constexpr char PartsPerMillion[] PROGMEM = "ppm";
-alignas(4) static constexpr char Lux[] PROGMEM = "lux";
-alignas(4) static constexpr char UltravioletIndex[] PROGMEM = "UVindex";
-alignas(4) static constexpr char Ohm[] PROGMEM = "ohm";
-alignas(4) static constexpr char MilligrammPerCubicMeter[] PROGMEM = "mg/m³";
-alignas(4) static constexpr char CountsPerMinute[] PROGMEM = "cpm";
-alignas(4) static constexpr char MicrosievertPerHour[] PROGMEM = "µSv/h";
-alignas(4) static constexpr char Meter[] PROGMEM = "m";
-alignas(4) static constexpr char Hertz[] PROGMEM = "Hz";
-alignas(4) static constexpr char Ph[] PROGMEM = "pH";
-alignas(4) static constexpr char None[] PROGMEM = "none";
+PROGMEM_STRING(Farenheit, "°F");
+PROGMEM_STRING(Celcius, "°C");
+PROGMEM_STRING(Kelvin, "K");
+PROGMEM_STRING(Percentage, "%");
+PROGMEM_STRING(Hectopascal, "hPa");
+PROGMEM_STRING(Ampere, "A");
+PROGMEM_STRING(Volt, "V");
+PROGMEM_STRING(Watt, "W");
+PROGMEM_STRING(Kilowatt, "kW");
+PROGMEM_STRING(Voltampere, "VA");
+PROGMEM_STRING(Kilovoltampere, "kVA");
+PROGMEM_STRING(VoltampereReactive, "VAR");
+PROGMEM_STRING(KilovoltampereReactive, "kVAR");
+PROGMEM_STRING(Joule, "J");
+PROGMEM_STRING(KilowattHour, "kWh");
+PROGMEM_STRING(MicrogrammPerCubicMeter, "µg/m³");
+PROGMEM_STRING(PartsPerMillion, "ppm");
+PROGMEM_STRING(Lux, "lux");
+PROGMEM_STRING(UltravioletIndex, "UVindex");
+PROGMEM_STRING(Ohm, "ohm");
+PROGMEM_STRING(MilligrammPerCubicMeter, "mg/m³");
+PROGMEM_STRING(CountsPerMinute, "cpm");
+PROGMEM_STRING(MicrosievertPerHour, "µSv/h");
+PROGMEM_STRING(Meter, "m");
+PROGMEM_STRING(Hertz, "Hz");
+PROGMEM_STRING(Ph, "pH");
+PROGMEM_STRING(None, "none");
 
 static constexpr espurna::settings::options::Enumeration<Unit> Options[] PROGMEM {
     {Unit::Farenheit, Farenheit},
@@ -976,49 +976,49 @@ static constexpr espurna::settings::options::Enumeration<Unit> Options[] PROGMEM
 namespace prefix {
 namespace {
 
-alignas(4) static constexpr char Sensor[] PROGMEM = "sns";
-alignas(4) static constexpr char Power[] PROGMEM = "pwr";
+PROGMEM_STRING(Sensor, "sns");
+PROGMEM_STRING(Power, "pwr");
 
-alignas(4) static constexpr char Temperature[] PROGMEM = "tmp";
-alignas(4) static constexpr char Humidity[] PROGMEM = "hum";
-alignas(4) static constexpr char Pressure[] PROGMEM = "press";
-alignas(4) static constexpr char Current[] PROGMEM = "curr";
-alignas(4) static constexpr char Voltage[] PROGMEM = "volt";
-alignas(4) static constexpr char PowerActive[] PROGMEM = "pwrP";
-alignas(4) static constexpr char PowerApparent[] PROGMEM = "pwrQ";
-alignas(4) static constexpr char PowerReactive[] PROGMEM = "pwrModS";
-alignas(4) static constexpr char PowerFactor[] PROGMEM = "pwrPF";
-alignas(4) static constexpr char Energy[] PROGMEM = "ene";
-alignas(4) static constexpr char EnergyDelta[] PROGMEM = "eneDelta";
-alignas(4) static constexpr char Analog[] PROGMEM = "analog";
-alignas(4) static constexpr char Digital[] PROGMEM = "digital";
-alignas(4) static constexpr char Event[] PROGMEM = "event";
-alignas(4) static constexpr char Pm1Dot0[] PROGMEM = "pm1dot0";
-alignas(4) static constexpr char Pm2Dot5[] PROGMEM = "pm2dot5";
-alignas(4) static constexpr char Pm10[] PROGMEM = "pm10";
-alignas(4) static constexpr char Co2[] PROGMEM = "co2";
-alignas(4) static constexpr char Voc[] PROGMEM = "voc";
-alignas(4) static constexpr char Iaq[] PROGMEM = "iaq";
-alignas(4) static constexpr char IaqAccuracy[] PROGMEM = "iaqAccuracy";
-alignas(4) static constexpr char IaqStatic[] PROGMEM = "iaqStatic";
-alignas(4) static constexpr char Lux[] PROGMEM = "lux";
-alignas(4) static constexpr char Uva[] PROGMEM = "uva";
-alignas(4) static constexpr char Uvb[] PROGMEM = "uvb";
-alignas(4) static constexpr char Uvi[] PROGMEM = "uvi";
-alignas(4) static constexpr char Distance[] PROGMEM = "distance";
-alignas(4) static constexpr char Hcho[] PROGMEM = "hcho";
-alignas(4) static constexpr char GeigerCpm[] PROGMEM = "gcpm";
-alignas(4) static constexpr char GeigerSievert[] PROGMEM = "gsiev";
-alignas(4) static constexpr char Count[] PROGMEM = "count";
-alignas(4) static constexpr char No2[] PROGMEM = "no2";
-alignas(4) static constexpr char Co[] PROGMEM = "co";
-alignas(4) static constexpr char Resistance[] PROGMEM = "res";
-alignas(4) static constexpr char Ph[] PROGMEM = "ph";
-alignas(4) static constexpr char Frequency[] PROGMEM = "freq";
-alignas(4) static constexpr char Tvoc[] PROGMEM = "tvoc";
-alignas(4) static constexpr char Ch2o[] PROGMEM = "ch2o";
+PROGMEM_STRING(Temperature, "tmp");
+PROGMEM_STRING(Humidity, "hum");
+PROGMEM_STRING(Pressure, "press");
+PROGMEM_STRING(Current, "curr");
+PROGMEM_STRING(Voltage, "volt");
+PROGMEM_STRING(PowerActive, "pwrP");
+PROGMEM_STRING(PowerApparent, "pwrQ");
+PROGMEM_STRING(PowerReactive, "pwrModS");
+PROGMEM_STRING(PowerFactor, "pwrPF");
+PROGMEM_STRING(Energy, "ene");
+PROGMEM_STRING(EnergyDelta, "eneDelta");
+PROGMEM_STRING(Analog, "analog");
+PROGMEM_STRING(Digital, "digital");
+PROGMEM_STRING(Event, "event");
+PROGMEM_STRING(Pm1Dot0, "pm1dot0");
+PROGMEM_STRING(Pm2Dot5, "pm2dot5");
+PROGMEM_STRING(Pm10, "pm10");
+PROGMEM_STRING(Co2, "co2");
+PROGMEM_STRING(Voc, "voc");
+PROGMEM_STRING(Iaq, "iaq");
+PROGMEM_STRING(IaqAccuracy, "iaqAccuracy");
+PROGMEM_STRING(IaqStatic, "iaqStatic");
+PROGMEM_STRING(Lux, "lux");
+PROGMEM_STRING(Uva, "uva");
+PROGMEM_STRING(Uvb, "uvb");
+PROGMEM_STRING(Uvi, "uvi");
+PROGMEM_STRING(Distance, "distance");
+PROGMEM_STRING(Hcho, "hcho");
+PROGMEM_STRING(GeigerCpm, "gcpm");
+PROGMEM_STRING(GeigerSievert, "gsiev");
+PROGMEM_STRING(Count, "count");
+PROGMEM_STRING(No2, "no2");
+PROGMEM_STRING(Co, "co");
+PROGMEM_STRING(Resistance, "res");
+PROGMEM_STRING(Ph, "ph");
+PROGMEM_STRING(Frequency, "freq");
+PROGMEM_STRING(Tvoc, "tvoc");
+PROGMEM_STRING(Ch2o, "ch2o");
 
-alignas(4) static constexpr char Unknown[] PROGMEM = "unknown";
+PROGMEM_STRING(Unknown, "unknown");
 
 constexpr StringView get(unsigned char type) {
     return (type == MAGNITUDE_TEMPERATURE) ? Temperature :
@@ -1068,19 +1068,19 @@ constexpr StringView get(unsigned char type) {
 namespace suffix {
 namespace {
 
-alignas(4) static constexpr char Units[] PROGMEM = "Units";
-alignas(4) static constexpr char Ratio[] PROGMEM = "Ratio";
-alignas(4) static constexpr char Correction[] PROGMEM = "Correction";
-alignas(4) static constexpr char ZeroThreshold[] PROGMEM = "ZeroThreshold";
-alignas(4) static constexpr char MinDelta[] PROGMEM = "MinDelta";
-alignas(4) static constexpr char MaxDelta[] PROGMEM = "MaxDelta";
+PROGMEM_STRING(Units, "Units");
+PROGMEM_STRING(Ratio, "Ratio");
+PROGMEM_STRING(Correction, "Correction");
+PROGMEM_STRING(ZeroThreshold, "ZeroThreshold");
+PROGMEM_STRING(MinDelta, "MinDelta");
+PROGMEM_STRING(MaxDelta, "MaxDelta");
 
-alignas(4) static constexpr char Mains[] PROGMEM = "Mains";
-alignas(4) static constexpr char Reference[] PROGMEM = "Reference";
+PROGMEM_STRING(Mains, "Mains");
+PROGMEM_STRING(Reference, "Reference");
 
-alignas(4) static constexpr char Total[] PROGMEM = "Total";
+PROGMEM_STRING(Total, "Total");
 
-alignas(4) static constexpr char Filter[] PROGMEM = "Filter";
+PROGMEM_STRING(Filter, "Filter");
 
 } // namespace
 } // namespace suffix
@@ -1088,11 +1088,11 @@ alignas(4) static constexpr char Filter[] PROGMEM = "Filter";
 namespace keys {
 namespace {
 
-alignas(4) static constexpr char ReadInterval[] PROGMEM = "snsRead";
-alignas(4) static constexpr char InitInterval[] PROGMEM = "snsInit";
-alignas(4) static constexpr char ReportEvery[] PROGMEM = "snsReport";
-alignas(4) static constexpr char SaveEvery[] PROGMEM = "snsSave";
-alignas(4) static constexpr char RealTimeValues[] PROGMEM = "snsRealTime";
+PROGMEM_STRING(ReadInterval, "snsRead");
+PROGMEM_STRING(InitInterval, "snsInit");
+PROGMEM_STRING(ReportEvery, "snsReport");
+PROGMEM_STRING(SaveEvery, "snsSave");
+PROGMEM_STRING(RealTimeValues, "snsRealTime");
 
 espurna::settings::Key get(espurna::StringView prefix, espurna::StringView suffix, size_t index) {
     String key;
@@ -1138,7 +1138,7 @@ bool realTimeValues() {
 } // namespace
 } // namespace settings
 
-alignas(4) static constexpr char List[] PROGMEM =
+alignas(4) static constexpr char List[] PROGMEM_STRING_ATTR =
 #if ADE7953_SUPPORT
     "ADE7953 "
 #endif
@@ -3664,7 +3664,7 @@ namespace {
 
 namespace commands {
 
-alignas(4) static constexpr char Magnitudes[] PROGMEM = "MAGNITUDES";
+PROGMEM_STRING(Magnitudes, "MAGNITUDES");
 
 void magnitudes(::terminal::CommandContext&& ctx) {
     if (!magnitude::count()) {
@@ -3685,7 +3685,7 @@ void magnitudes(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Expected[] PROGMEM = "EXPECTED";
+PROGMEM_STRING(Expected, "EXPECTED");
 
 void expected(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 3) {
@@ -3709,14 +3709,14 @@ void expected(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("EXPECTED <ID> <VALUE>"));
 }
 
-alignas(4) static constexpr char ResetRatios[] PROGMEM = "RESET.RATIOS";
+PROGMEM_STRING(ResetRatios, "RESET.RATIOS");
 
 void reset_ratios(::terminal::CommandContext&& ctx) {
     energy::reset();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Energy[] PROGMEM = "ENERGY";
+PROGMEM_STRING(Energy, "ENERGY");
 
 void energy(::terminal::CommandContext&& ctx) {
     using IndexType = decltype(Magnitude::index_global);
diff --git a/code/espurna/sensors/PZEM004TSensor.h b/code/espurna/sensors/PZEM004TSensor.h
index 920640e6..4b44fd68 100644
--- a/code/espurna/sensors/PZEM004TSensor.h
+++ b/code/espurna/sensors/PZEM004TSensor.h
@@ -591,7 +591,7 @@ constexpr BaseEmonSensor::Magnitude PZEM004TSensor::Magnitudes[];
 #endif
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char PzemDevices[] PROGMEM = "PZ.DEVICES";
+PROGMEM_STRING(PzemDevices, "PZ.DEVICES");
 
 void PZEM004TSensor::command_devices(::terminal::CommandContext&& ctx) {
     foreach([&](const PZEM004TSensor&, const IPAddress& address) {
@@ -600,7 +600,7 @@ void PZEM004TSensor::command_devices(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char PzemPorts[] PROGMEM = "PZ.PORTS";
+PROGMEM_STRING(PzemPorts, "PZ.PORTS");
 
 void PZEM004TSensor::command_ports(::terminal::CommandContext&& ctx) {
     auto it = _ports.begin();
@@ -646,7 +646,7 @@ void PZEM004TSensor::command_ports(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char PzemAddress[] PROGMEM = "PZ.ADDRESS";
+PROGMEM_STRING(PzemAddress, "PZ.ADDRESS");
 
 // Set the *currently connected* device address
 // (ref. comment at the top, shouldn't do this when multiple devices are connected)
diff --git a/code/espurna/sensors/PZEM004TV30Sensor.h b/code/espurna/sensors/PZEM004TV30Sensor.h
index 8a6989bf..6c8e4e3a 100644
--- a/code/espurna/sensors/PZEM004TV30Sensor.h
+++ b/code/espurna/sensors/PZEM004TV30Sensor.h
@@ -608,7 +608,7 @@ constexpr espurna::duration::Milliseconds PZEM004TV30Sensor::DefaultUpdateInterv
 
 PZEM004TV30Sensor::Instance PZEM004TV30Sensor::_instance{};
 
-alignas(4) static constexpr char PzemV3Address[] PROGMEM = "PZ.ADDRESS";
+PROGMEM_STRING(PzemV3Address, "PZ.ADDRESS");
 
 void PZEM004TV30Sensor::command_address(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
diff --git a/code/espurna/settings.cpp b/code/espurna/settings.cpp
index 6523a555..e8efe507 100644
--- a/code/espurna/settings.cpp
+++ b/code/espurna/settings.cpp
@@ -300,7 +300,7 @@ void dump(const ::terminal::CommandContext& ctx, const query::IndexedSetting* be
 
 namespace commands {
 
-alignas(4) static constexpr char Config[] PROGMEM = "CONFIG";
+PROGMEM_STRING(Config, "CONFIG");
 
 void config(::terminal::CommandContext&& ctx) {
     DynamicJsonBuffer jsonBuffer(1024);
@@ -310,7 +310,7 @@ void config(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Keys[] PROGMEM = "KEYS";
+PROGMEM_STRING(Keys, "KEYS");
 
 void keys(::terminal::CommandContext&& ctx) {
     const auto keys = settings::sorted_keys();
@@ -333,7 +333,7 @@ void keys(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Gc[] PROGMEM = "GC";
+PROGMEM_STRING(Gc, "GC");
 
 void gc(::terminal::CommandContext&& ctx) {
     struct KeyRef {
@@ -379,7 +379,7 @@ void gc(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Del[] PROGMEM = "DEL";
+PROGMEM_STRING(Del, "DEL");
 
 void del(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() < 2) {
@@ -399,7 +399,7 @@ void del(::terminal::CommandContext&& ctx) {
     }
 }
 
-alignas(4) static constexpr char Set[] PROGMEM = "SET";
+PROGMEM_STRING(Set, "SET");
 
 void set(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 3) {
@@ -415,7 +415,7 @@ void set(::terminal::CommandContext&& ctx) {
     terminalError(ctx, F("could not set the key"));
 }
 
-alignas(4) static constexpr char Get[] PROGMEM = "GET";
+PROGMEM_STRING(Get, "GET");
 
 void get(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() < 2) {
@@ -442,14 +442,14 @@ void get(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Reload[] PROGMEM = "RELOAD";
+PROGMEM_STRING(Reload, "RELOAD");
 
 void reload(::terminal::CommandContext&& ctx) {
     espurnaReload();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char FactoryReset[] PROGMEM = "FACTORY.RESET";
+PROGMEM_STRING(FactoryReset, "FACTORY.RESET");
 
 void factory_reset(::terminal::CommandContext&& ctx) {
     factoryReset();
@@ -457,7 +457,7 @@ void factory_reset(::terminal::CommandContext&& ctx) {
 }
 
 [[gnu::unused]]
-alignas(4) static constexpr char Save[] PROGMEM = "SAVE";
+PROGMEM_STRING(Save, "SAVE");
 
 [[gnu::unused]]
 void save(::terminal::CommandContext&& ctx) {
diff --git a/code/espurna/storage_eeprom.cpp b/code/espurna/storage_eeprom.cpp
index 779b9a36..9d5c4a7a 100644
--- a/code/espurna/storage_eeprom.cpp
+++ b/code/espurna/storage_eeprom.cpp
@@ -71,7 +71,7 @@ void eepromBackup(uint32_t index){
 }
 
 #if TERMINAL_SUPPORT
-alignas(4) static constexpr char EepromCommand[] PROGMEM = "EEPROM";
+PROGMEM_STRING(EepromCommand, "EEPROM");
 
 static void _eepromCommand(::terminal::CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("Sectors: %s, current: %lu\n"),
@@ -83,21 +83,21 @@ static void _eepromCommand(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char EepromCommit[] PROGMEM = "EEPROM.COMMIT";
+PROGMEM_STRING(EepromCommit, "EEPROM.COMMIT");
 
 static void _eepromCommandCommit(::terminal::CommandContext&& ctx) {
     _eepromCommit();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char EepromDump[] PROGMEM = "EEPROM.DUMP";
+PROGMEM_STRING(EepromDump, "EEPROM.DUMP");
 
 static void _eepromCommandDump(::terminal::CommandContext&& ctx) {
     EEPROMr.dump(static_cast<Stream&>(ctx.output)); // XXX: only Print interface is used
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char FlashDump[] PROGMEM = "FLASH.DUMP";
+PROGMEM_STRING(FlashDump, "FLASH.DUMP");
 
 static void _flashCommandDump(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() < 2) {
diff --git a/code/espurna/system.cpp b/code/espurna/system.cpp
index 6af01cce..1c54ac4f 100644
--- a/code/espurna/system.cpp
+++ b/code/espurna/system.cpp
@@ -45,9 +45,9 @@ namespace {
 namespace settings {
 namespace options {
 
-alignas(4) static constexpr char None[] PROGMEM = "none";
-alignas(4) static constexpr char Once[] PROGMEM = "once";
-alignas(4) static constexpr char Repeat[] PROGMEM = "repeat";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(Once, "once");
+PROGMEM_STRING(Repeat, "repeat");
 
 static constexpr espurna::settings::options::Enumeration<heartbeat::Mode> HeartbeatModeOptions[] PROGMEM {
     {heartbeat::Mode::None, None},
@@ -59,9 +59,9 @@ static constexpr espurna::settings::options::Enumeration<heartbeat::Mode> Heartb
 
 namespace keys {
 
-alignas(4) static constexpr char Hostname[] PROGMEM = "hostname";
-alignas(4) static constexpr char Description[] PROGMEM = "desc";
-alignas(4) static constexpr char Password[] PROGMEM = "adminPass";
+PROGMEM_STRING(Hostname, "hostname");
+PROGMEM_STRING(Description, "desc");
+PROGMEM_STRING(Password, "adminPass");
 
 } // namespace keys
 
@@ -133,8 +133,8 @@ namespace {
 
 namespace internal {
 
-alignas(4) static constexpr char Hostname[] PROGMEM = HOSTNAME;
-alignas(4) static constexpr char Password[] PROGMEM = ADMIN_PASS;
+PROGMEM_STRING(Hostname, HOSTNAME);
+PROGMEM_STRING(Password, ADMIN_PASS);
 
 } // namespace internal
 
@@ -875,9 +875,9 @@ constexpr Mask value() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Mode[] PROGMEM = "hbMode";
-alignas(4) static constexpr char Interval[] PROGMEM = "hbInterval";
-alignas(4) static constexpr char Report[] PROGMEM = "hbReport";
+PROGMEM_STRING(Mode, "hbMode");
+PROGMEM_STRING(Interval, "hbInterval");
+PROGMEM_STRING(Report, "hbReport");
 
 } // namespace keys
 
diff --git a/code/espurna/telnet.cpp b/code/espurna/telnet.cpp
index ce81c97e..de579dcf 100644
--- a/code/espurna/telnet.cpp
+++ b/code/espurna/telnet.cpp
@@ -75,11 +75,11 @@ constexpr bool authentication() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Prefix[] PROGMEM = "telnet";
+PROGMEM_STRING(Prefix, "telnet");
 
-alignas(4) static constexpr char Station[] PROGMEM = "telnetSTA";
-alignas(4) static constexpr char Authentication[] PROGMEM = "telnetAuth";
-alignas(4) static constexpr char Port[] PROGMEM = "telnetPort";
+PROGMEM_STRING(Station, "telnetSTA");
+PROGMEM_STRING(Authentication, "telnetAuth");
+PROGMEM_STRING(Port, "telnetPort");
 
 } // namespace keys
 
@@ -268,9 +268,9 @@ private:
 
 namespace message {
 
-alignas(4) static constexpr char PasswordRequest[] = "Password (disconnects after 1 failed attempt): ";
-alignas(4) static constexpr char InvalidPassword[] = "-ERROR: Invalid password\n";
-alignas(4) static constexpr char OkPassword[] = "+OK\n";
+PROGMEM_STRING(PasswordRequest, "Password (disconnects after 1 failed attempt): ");
+PROGMEM_STRING(InvalidPassword, "-ERROR: Invalid password\n");
+PROGMEM_STRING(OkPassword, "+OK\n");
 
 } // namespace message
 
@@ -864,7 +864,7 @@ bool connect(Address address) {
 namespace terminal {
 namespace commands {
 
-alignas(4) static constexpr char Reverse[] PROGMEM = "TELNET.REVERSE";
+PROGMEM_STRING(Reverse, "TELNET.REVERSE");
 
 void reverse(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 3) {
diff --git a/code/espurna/terminal.cpp b/code/espurna/terminal.cpp
index 48fd0fa4..bf272011 100644
--- a/code/espurna/terminal.cpp
+++ b/code/espurna/terminal.cpp
@@ -60,8 +60,8 @@ constexpr size_t serialPort() {
 
 namespace commands {
 
-alignas(4) static constexpr char Commands[] PROGMEM = "COMMANDS";
-alignas(4) static constexpr char Help[] PROGMEM = "HELP";
+PROGMEM_STRING(Commands, "COMMANDS");
+PROGMEM_STRING(Help, "HELP");
 
 void help(CommandContext&& ctx) {
     auto names = terminal::names();
@@ -83,14 +83,14 @@ void help(CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Reset[] PROGMEM = "RESET";
+PROGMEM_STRING(Reset, "RESET");
 
 void reset(CommandContext&& ctx) {
     prepareReset(CustomResetReason::Terminal);
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char EraseConfig[] PROGMEM = "ERASE.CONFIG";
+PROGMEM_STRING(EraseConfig, "ERASE.CONFIG");
 
 void erase_config(CommandContext&& ctx) {
     terminalOK(ctx);
@@ -98,7 +98,7 @@ void erase_config(CommandContext&& ctx) {
     forceEraseSDKConfig();
 }
 
-alignas(4) static constexpr char Heap[] PROGMEM = "HEAP";
+PROGMEM_STRING(Heap, "HEAP");
 
 void heap(CommandContext&& ctx) {
     const auto stats = systemHeapStats();
@@ -108,7 +108,7 @@ void heap(CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Uptime[] PROGMEM = "UPTIME";
+PROGMEM_STRING(Uptime, "UPTIME");
 
 void uptime(CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("uptime %s\n"),
@@ -116,7 +116,7 @@ void uptime(CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Info[] PROGMEM = "INFO";
+PROGMEM_STRING(Info, "INFO");
 
 void info(CommandContext&& ctx) {
     const auto app = buildApp();
@@ -276,7 +276,7 @@ StringView flash_chip_mode() {
     return out;
 }
 
-alignas(4) static constexpr char Storage[] PROGMEM = "STORAGE";
+PROGMEM_STRING(Storage, "STORAGE");
 
 void storage(CommandContext&& ctx) {
     ctx.output.printf_P(PSTR("flash chip ID: 0x%06X\n"), ESP.getFlashChipId());
@@ -317,7 +317,7 @@ void storage(CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Adc[] PROGMEM = "ADC";
+PROGMEM_STRING(Adc, "ADC");
 
 void adc(CommandContext&& ctx) {
     const int pin = (ctx.argv.size() == 2)
@@ -329,21 +329,21 @@ void adc(CommandContext&& ctx) {
 }
 
 #if SYSTEM_CHECK_ENABLED
-alignas(4) static constexpr char Stable[] PROGMEM = "STABLE";
+PROGMEM_STRING(Stable, "STABLE");
 
 void stable(CommandContext&& ctx) {
     systemForceStable();
     prepareReset(CustomResetReason::Stability);
 }
 
-alignas(4) static constexpr char Unstable[] PROGMEM = "UNSTABLE";
+PROGMEM_STRING(Unstable, "UNSTABLE");
 
 void unstable(CommandContext&& ctx) {
     systemForceUnstable();
     prepareReset(CustomResetReason::Stability);
 }
 
-alignas(4) static constexpr char Trap[] PROGMEM = "TRAP";
+PROGMEM_STRING(Trap, "TRAP");
 
 void trap(CommandContext&& ctx) {
     __builtin_trap();
@@ -606,12 +606,12 @@ void onVisible(JsonObject& root) {
 }
 
 void onAction(uint32_t client_id, const char* action, JsonObject& data) {
-    alignas(4) static constexpr char Cmd[] PROGMEM = "cmd";
+    PROGMEM_STRING(Cmd, "cmd");
     if (strncmp_P(action, &Cmd[0], __builtin_strlen(Cmd)) != 0) {
         return;
     }
 
-    alignas(4) static constexpr char Line[] PROGMEM = "line";
+    PROGMEM_STRING(Line, "line");
     if (!data.containsKey(FPSTR(Line)) || !data[FPSTR(Line)].is<String>()) {
         return;
     }
diff --git a/code/espurna/thingspeak.cpp b/code/espurna/thingspeak.cpp
index b1809a55..0ce6a6b9 100644
--- a/code/espurna/thingspeak.cpp
+++ b/code/espurna/thingspeak.cpp
@@ -47,8 +47,8 @@ static constexpr auto FlushInterval = espurna::duration::Milliseconds(THINGSPEAK
 static constexpr size_t Retries { THINGSPEAK_TRIES };
 static constexpr size_t BufferSize { 256 };
 
-alignas(4) static constexpr char ApiKey[] PROGMEM = THINGSPEAK_APIKEY;
-alignas(4) static constexpr char Address[] PROGMEM = THINGSPEAK_ADDRESS;
+PROGMEM_STRING(ApiKey, THINGSPEAK_APIKEY);
+PROGMEM_STRING(Address, THINGSPEAK_ADDRESS);
 
 constexpr bool enabled() {
     return 1 == THINGSPEAK_ENABLED;
@@ -63,18 +63,18 @@ constexpr bool clearCache() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "tspkEnabled";
-alignas(4) static constexpr char ApiKey[] PROGMEM = "tspkKey";
-alignas(4) static constexpr char ClearCache[] PROGMEM = "tspkClear";
-alignas(4) static constexpr char Address[] PROGMEM = "tspkAddress";
+PROGMEM_STRING(Enabled, "tspkEnabled");
+PROGMEM_STRING(ApiKey, "tspkKey");
+PROGMEM_STRING(ClearCache, "tspkClear");
+PROGMEM_STRING(Address, "tspkAddress");
 
-alignas(4) static constexpr char Relay[] PROGMEM = "tspkRelay";
-alignas(4) static constexpr char Magnitude[] PROGMEM = "tspkMagnitude";
+PROGMEM_STRING(Relay, "tspkRelay");
+PROGMEM_STRING(Magnitude, "tspkMagnitude");
 
 #if THINGSPEAK_USE_SSL && (SECURE_CLIENT != SECURE_CLIENT_NONE)
-alignas(4) static constexpr char Check[] PROGMEM = "tspkScCheck";
-alignas(4) static constexpr char Fingerprint[] PROGMEM = "tspkFP";
-alignas(4) static constexpr char Mfln[] PROGMEM = "tspkMfln";
+PROGMEM_STRING(Check, "tspkScCheck");
+PROGMEM_STRING(Fingerprint, "tspkFP");
+PROGMEM_STRING(Mfln, "tspkMfln");
 #endif
 
 } // namespace keys
@@ -222,8 +222,8 @@ namespace {
 static constexpr int Check { THINGSPEAK_SECURE_CLIENT_CHECK };
 static constexpr uint16_t Mfln { THINGSPEAK_SECURE_CLIENT_MFLN };
 
-alignas(4) static constexpr char Tag[] PROGMEM = "THINGSPEAK";
-alignas(4) static constexpr char Fingerprint[] PROGMEM = THINGSPEAK_FINGERPRINT;
+PROGMEM_STRING(Tag, "THINGSPEAK");
+PROGMEM_STRING(Fingerprint, THINGSPEAK_FINGERPRINT);
 
 SecureClientConfig secure_config {
     .tag = Tag,
@@ -471,8 +471,8 @@ private:
             return;
         }
 
-        alignas(4) static constexpr char Status[] PROGMEM = "HTTP/1.1 200 OK";
-        alignas(4) static constexpr char Break[] PROGMEM = "\r\n\r\n";
+        PROGMEM_STRING(Status, "HTTP/1.1 200 OK");
+        PROGMEM_STRING(Break, "\r\n\r\n");
 
         auto begin = reinterpret_cast<const char*>(data);
         auto end = begin + len;
@@ -679,7 +679,7 @@ void loop() {
 namespace web {
 namespace {
 
-alignas(4) static constexpr char Prefix[] PROGMEM = "tspk";
+PROGMEM_STRING(Prefix, "tspk");
 
 bool onKeyCheck(StringView key, const JsonVariant&) {
     return espurna::settings::query::samePrefix(key, Prefix);
diff --git a/code/espurna/tuya.cpp b/code/espurna/tuya.cpp
index 68617615..9825f8f2 100644
--- a/code/espurna/tuya.cpp
+++ b/code/espurna/tuya.cpp
@@ -604,7 +604,7 @@ error:
 #endif
 
 #if TERMINAL_SUPPORT
-    alignas(4) static constexpr char TuyaShow[] PROGMEM = "TUYA.SHOW";
+    PROGMEM_STRING(TuyaShow, "TUYA.SHOW");
 
     static void terminalShow(::terminal::CommandContext&& ctx) {
         ctx.output.printf_P(PSTR("Product: %s\n"), product.length() ? product.c_str() : "(unknown)");
@@ -636,7 +636,7 @@ error:
         }
     }
 
-    alignas(4) static constexpr char TuyaSave[] PROGMEM = "TUYA.SAVE";
+    PROGMEM_STRING(TuyaSave, "TUYA.SAVE");
 
     static void terminalSave(::terminal::CommandContext&& ctx) {
         for (auto& kv : config) {
diff --git a/code/espurna/types.h b/code/espurna/types.h
index f13f7ade..7c97d755 100644
--- a/code/espurna/types.h
+++ b/code/espurna/types.h
@@ -341,13 +341,19 @@ inline String operator+=(String& lhs, StringView rhs) {
     return lhs;
 }
 
+#define PROGMEM_STRING_ATTR __attribute__((section( "\".irom0.pstr." __FILE__ "." __STRINGIZE(__LINE__) "."  __STRINGIZE(__COUNTER__) "\", \"aSM\", @progbits, 1 #")))
+
+#define PROGMEM_STRING(NAME, X)\
+        alignas(4) static constexpr char NAME[] PROGMEM_STRING_ATTR = (X)
+
+
 #define STRING_VIEW(X) ({\
-        alignas(4) static constexpr char __pstr__[] PROGMEM = (X);\
+        alignas(4) static constexpr char __pstr__[] PROGMEM_STRING_ATTR = (X);\
         ::espurna::StringView{__pstr__};\
     })
 
 #define STRING_VIEW_INLINE(NAME, X)\
-        alignas(4) static constexpr char __pstr__ ## NAME ##  __ [] PROGMEM = (X);\
+        alignas(4) static constexpr char __pstr__ ## NAME ##  __ [] PROGMEM_STRING_ATTR = (X);\
         constexpr auto NAME = ::espurna::StringView(__pstr__ ## NAME ## __)
 
 } // namespace espurna
diff --git a/code/espurna/uart.cpp b/code/espurna/uart.cpp
index ee0cadc2..1ec481e3 100644
--- a/code/espurna/uart.cpp
+++ b/code/espurna/uart.cpp
@@ -45,9 +45,9 @@ namespace settings {
 namespace internal {
 namespace {
 
-alignas(4) static constexpr char ParityNone[] PROGMEM = "none";
-alignas(4) static constexpr char ParityEven[] PROGMEM = "even";
-alignas(4) static constexpr char ParityOdd[] PROGMEM = "odd";
+PROGMEM_STRING(ParityNone, "none");
+PROGMEM_STRING(ParityEven, "even");
+PROGMEM_STRING(ParityOdd, "odd");
 
 static constexpr std::array<settings::options::Enumeration<driver::uart::Parity>, 3> ParityOptions PROGMEM {
     {{driver::uart::Parity::None, ParityNone},
@@ -183,16 +183,16 @@ constexpr ::SerialConfig from_config(Config config) {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char TxPin[] PROGMEM = "uartTx";
-alignas(4) static constexpr char RxPin[] PROGMEM = "uartRx";
+PROGMEM_STRING(TxPin, "uartTx");
+PROGMEM_STRING(RxPin, "uartRx");
 
-alignas(4) static constexpr char Baudrate[] PROGMEM = "uartBaud";
+PROGMEM_STRING(Baudrate, "uartBaud");
 
-alignas(4) static constexpr char DataBits[] PROGMEM = "uartDataBits";
-alignas(4) static constexpr char StopBits[] PROGMEM = "uartStopBits";
-alignas(4) static constexpr char Parity[] PROGMEM = "uartParity";
+PROGMEM_STRING(DataBits, "uartDataBits");
+PROGMEM_STRING(StopBits, "uartStopBits");
+PROGMEM_STRING(Parity, "uartParity");
 
-alignas(4) static constexpr char Invert[] PROGMEM = "uartInv";
+PROGMEM_STRING(Invert, "uartInv");
 
 } // namespace keys
 
@@ -426,7 +426,7 @@ static constexpr espurna::settings::query::IndexedSetting IndexedSettings[] PROG
 };
 
 bool checkSamePrefix(StringView key) {
-    alignas(4) static constexpr char Prefix[] PROGMEM = "uart";
+    PROGMEM_STRING(Prefix, "uart");
     return espurna::settings::query::samePrefix(key, Prefix);
 }
 
@@ -502,7 +502,7 @@ void uart(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Uart[] PROGMEM = "UART";
+PROGMEM_STRING(Uart, "UART");
 
 static constexpr ::terminal::Command List[] PROGMEM {
     {Uart, commands::uart},
diff --git a/code/espurna/web.cpp b/code/espurna/web.cpp
index 4c557c05..ee13a6ae 100644
--- a/code/espurna/web.cpp
+++ b/code/espurna/web.cpp
@@ -215,7 +215,7 @@ size_t AsyncWebPrint::write(const uint8_t* data, size_t size) {
 
 namespace {
 
-alignas(4) static constexpr char LastModified[] PROGMEM = __DATE__ " " __TIME__ " GMT";
+PROGMEM_STRING(LastModified, __DATE__ " " __TIME__ " GMT");
 static constexpr size_t WebConfigBufferMax { 4096 };
 
 // server instance can't (yet) be static, port is the ctor argument :/
@@ -467,7 +467,7 @@ void _onAPCaptiveRequest(AsyncWebServerRequest* request) {
 #endif
 
 #if WEB_EMBEDDED
-alignas(4) static constexpr char IfModifiedSince[] PROGMEM = "If-Modified-Since";
+PROGMEM_STRING(IfModifiedSince, "If-Modified-Since");
 
 void _onHome(AsyncWebServerRequest *request) {
     if (!_isAPModeRequest(request) && !_authenticateRequest(request)) {
diff --git a/code/espurna/wifi.cpp b/code/espurna/wifi.cpp
index b2c86039..1a0a6289 100644
--- a/code/espurna/wifi.cpp
+++ b/code/espurna/wifi.cpp
@@ -68,9 +68,9 @@ namespace ap {
 namespace settings {
 namespace options {
 
-alignas(4) static constexpr char Disabled[] PROGMEM = "off";
-alignas(4) static constexpr char Enabled[] PROGMEM = "on";
-alignas(4) static constexpr char Fallback[] PROGMEM = "fallback";
+PROGMEM_STRING(Disabled, "off");
+PROGMEM_STRING(Enabled, "on");
+PROGMEM_STRING(Fallback, "fallback");
 
 static constexpr espurna::settings::options::Enumeration<wifi::ApMode> ApModeOptions[] PROGMEM {
     {wifi::ApMode::Disabled, Disabled},
@@ -85,9 +85,9 @@ static constexpr espurna::settings::options::Enumeration<wifi::ApMode> ApModeOpt
 namespace settings {
 namespace options {
 
-alignas(4) static constexpr char None[] PROGMEM = "none";
-alignas(4) static constexpr char Modem[] PROGMEM = "modem";
-alignas(4) static constexpr char Light[] PROGMEM = "light";
+PROGMEM_STRING(None, "none");
+PROGMEM_STRING(Modem, "modem");
+PROGMEM_STRING(Light, "light");
 
 static constexpr espurna::settings::options::Enumeration<WiFiSleepType_t> WiFiSleepTypeOptions[] PROGMEM {
     {WIFI_NONE_SLEEP, None},
@@ -465,8 +465,8 @@ String opmode(uint8_t mode) {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char TxPower[] PROGMEM = "wifiTxPwr";
-alignas(4) static constexpr char Sleep[] PROGMEM = "wifiSleep";
+PROGMEM_STRING(TxPower, "wifiTxPwr");
+PROGMEM_STRING(Sleep, "wifiSleep");
 
 } // namespace keys
 
@@ -898,18 +898,18 @@ constexpr uint8_t channel(size_t index) {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Mode[] PROGMEM = "wifiStaMode";
+PROGMEM_STRING(Mode, "wifiStaMode");
 
-alignas(4) static constexpr char Ssid[] PROGMEM = "ssid";
-alignas(4) static constexpr char Passphrase[] PROGMEM = "pass";
+PROGMEM_STRING(Ssid, "ssid");
+PROGMEM_STRING(Passphrase, "pass");
 
-alignas(4) static constexpr char Ip[] PROGMEM = "ip";
-alignas(4) static constexpr char Gateway[] PROGMEM = "gw";
-alignas(4) static constexpr char Netmask[] PROGMEM = "mask";
-alignas(4) static constexpr char Dns[] PROGMEM = "dns";
+PROGMEM_STRING(Ip, "ip");
+PROGMEM_STRING(Gateway, "gw");
+PROGMEM_STRING(Netmask, "mask");
+PROGMEM_STRING(Dns, "dns");
 
-alignas(4) static constexpr char Bssid[] PROGMEM = "bssid";
-alignas(4) static constexpr char Channel[] PROGMEM = "chan";
+PROGMEM_STRING(Bssid, "bssid");
+PROGMEM_STRING(Channel, "chan");
 
 } // namespace keys
 
@@ -1159,7 +1159,7 @@ namespace scan {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Enabled[] PROGMEM = "wifiScan";
+PROGMEM_STRING(Enabled, "wifiScan");
 
 } // namespace keys
 } // namespace settings
@@ -1708,7 +1708,7 @@ constexpr int8_t threshold() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Threshold[] PROGMEM = "wifiScanRssi";
+PROGMEM_STRING(Threshold, "wifiScanRssi");
 
 } // namespace keys
 
@@ -1913,14 +1913,14 @@ constexpr uint8_t channel() {
 namespace settings {
 namespace keys {
 
-alignas(4) static constexpr char Mode[] PROGMEM = "wifiApMode";
+PROGMEM_STRING(Mode, "wifiApMode");
 
-alignas(4) static constexpr char Ssid[] PROGMEM = "wifiApSsid";
-alignas(4) static constexpr char Passphrase[] PROGMEM = "wifiApPass";
+PROGMEM_STRING(Ssid, "wifiApSsid");
+PROGMEM_STRING(Passphrase, "wifiApPass");
 
-alignas(4) static constexpr char Channel[] PROGMEM = "wifiApChan";
+PROGMEM_STRING(Channel, "wifiApChan");
 
-[[gnu::unused]] alignas(4) static constexpr char Captive[] PROGMEM = "wifiApCaptive";
+[[gnu::unused]] PROGMEM_STRING(Captive, "wifiApCaptive");
 
 } // namespace keys
 
@@ -2181,7 +2181,7 @@ bool checkIndexedPrefix(StringView key) {
 
 // generic 'ap' and 'modem' configuration
 bool checkExactPrefix(StringView key) {
-    alignas(4) static constexpr char Prefix[] PROGMEM = "wifi";
+    PROGMEM_STRING(Prefix, "wifi");
     if (espurna::settings::query::samePrefix(key, Prefix)) {
         return true;
     }
@@ -2235,7 +2235,7 @@ void configure() {
 namespace terminal {
 namespace commands {
 
-alignas(4) static constexpr char Stations[] PROGMEM = "WIFI.STATIONS";
+PROGMEM_STRING(Stations, "WIFI.STATIONS");
 
 void stations(::terminal::CommandContext&& ctx) {
     size_t stations { 0ul };
@@ -2255,7 +2255,7 @@ void stations(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Network[] PROGMEM = "NETWORK";
+PROGMEM_STRING(Network, "NETWORK");
 
 void network(::terminal::CommandContext&& ctx) {
     for (auto& addr : addrList) {
@@ -2294,7 +2294,7 @@ void network(::terminal::CommandContext&& ctx) {
     }
 }
 
-alignas(4) static constexpr char Wifi[] PROGMEM = "WIFI";
+PROGMEM_STRING(Wifi, "WIFI");
 
 void wifi(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() == 2) {
@@ -2341,7 +2341,7 @@ void wifi(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Reset[] PROGMEM = "WIFI.RESET";
+PROGMEM_STRING(Reset, "WIFI.RESET");
 
 void reset(::terminal::CommandContext&& ctx) {
     wifi::sta::disconnect();
@@ -2349,21 +2349,21 @@ void reset(::terminal::CommandContext&& ctx) {
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Station[] PROGMEM = "WIFI.STA";
+PROGMEM_STRING(Station, "WIFI.STA");
 
 void station(::terminal::CommandContext&& ctx) {
     wifi::sta::toggle();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char AccessPoint[] PROGMEM = "WIFI.AP";
+PROGMEM_STRING(AccessPoint, "WIFI.AP");
 
 void access_point(::terminal::CommandContext&& ctx) {
     wifi::ap::toggle();
     terminalOK(ctx);
 }
 
-alignas(4) static constexpr char Scan[] PROGMEM = "WIFI.SCAN";
+PROGMEM_STRING(Scan, "WIFI.SCAN");
 
 void scan(::terminal::CommandContext&& ctx) {
     wifi::sta::scan::wait(
diff --git a/code/espurna/ws.cpp b/code/espurna/ws.cpp
index 3dd44c62..fcda3fd0 100644
--- a/code/espurna/ws.cpp
+++ b/code/espurna/ws.cpp
@@ -34,7 +34,7 @@ namespace {
 
 namespace internal {
 
-alignas(4) static constexpr char SchemaKey[] PROGMEM = "schema";
+PROGMEM_STRING(SchemaKey, "schema");
 
 } // namespace internal
 
@@ -822,7 +822,7 @@ bool wsConnected(uint32_t client_id) {
 }
 
 void wsPayloadModule(JsonObject& root, const char* name) {
-    alignas(4) static constexpr char Key[] PROGMEM = "modulesVisible";
+    PROGMEM_STRING(Key, "modulesVisible");
     JsonArray& modules = root.containsKey(FPSTR(Key))
         ? root[FPSTR(Key)]
         : root.createNestedArray(FPSTR(Key));