Feature Configuration

The Feature Configuration page controls modules that were compiled into the firmware. Settings are stored in LittleFS at /config/features.json and take effect after Save and Restart.

Activation Rules

compiled AND userEnabled AND budgetPassed AND NOT runtimeDisabled

Field	Meaning
compiled	The firmware contains the feature code
userEnabled	The user enabled the feature
budgetPassed	The startup DRAM/PSRAM budget check passed
runtimeDisabled	Runtime memory protection temporarily stopped the feature
active	The feature and all dependencies are currently available
locked	The build or partition cannot support the feature
deferred	Initialization is waiting for the network

If memory is insufficient, initialization is skipped, a [BUDGET] message is logged, and /api/system/status reports no-memory. The budget is evaluated again at restart.

Core management entries such as Device Config, Network Config, and Feature Configuration remain visible. An optional feature menu is visible only when the feature is compiled and active. A feature excluded from the build is locked and labeled Not compiled into firmware.

Memory Degradation

At SEVERE memory pressure, the system keeps network and Web management available first. MQTTS falls back to MQTT, while Modbus, Peripheral Exec workers and timers, scripts, and memory-heavy optional peripherals may pause. Their JSON configuration is not deleted. Services are rebuilt when memory recovers.

If pressure remains CRITICAL, MQTT may be persistently disabled. Save and enable it again from Protocol Configuration after resolving the memory shortage.

Release Defaults

Release environments share a common feature baseline, with hardware-specific overrides for capabilities such as OTA and IR.

Group	Feature Keys	Default	Notes
Network	webServer, mdns	On	Keeps the management entry available
Peripherals	lcd, neopixel, sevenSegment, ds18b20	Off	Enable only with matching hardware
Peripherals	lcdGb2312, i2cSensors, rfid, irRemote, rfLearn, ds1302, lcd1602	Off	Depends on LCD, I2C, SPI, RMT, or three-wire hardware
Protocols	modbus, mqtts	Off	MQTTS depends on MQTT; Modbus needs UART/RS485
Automation	ruleScript, commandScript	Off	commandScript depends on ruleScript
System	deviceControl, ota, logViewer, fileLogging, userAdmin	Off	OTA also requires an A/B partition
Network extensions	ethernet, cellular, ble	Off	Requires matching hardware; BLE is not a release path

Use the page or /api/features/status as the source of truth for the current build. The 4MB environments lock OTA. esp32-F4R0, esp32c3-F4R0, esp32c6-F4R0, and esp32c6-F8R0 do not compile Ethernet or Cellular support.

Apply a Change

1. Open Feature Configuration in the device Web console.
2. Check the compile state and hardware dependency before enabling a feature.
3. Save and restart the device.
4. Confirm active and review Health Monitor after restart.

Runtime switches do not reduce the firmware image size. Flash-size reduction requires changing build flags in platformio.ini and rebuilding the firmware and Web assets.

features.json stores the complete requested state. A legacy sparse file keeps its existing choices and is expanded after the first successful load. Use configuration export/import for migration instead of editing a live filesystem.

API Summary

Endpoint	Purpose
GET /api/features/status	Return feature states and the resource summary
POST /api/features/config	Save switches without restarting
POST /api/features/estimate	Estimate Flash/RAM use without saving
POST /api/features/apply	Save settings and schedule a restart

Clients should wait for a successful apply response, then poll /api/health. A network-dependent feature may temporarily report deferred during startup. Low-memory Web requests may return 503; honor Retry-After before retrying.