Web Portal

ESPGeiger comes with a built-in Web Portal, allowing you to easy configuration of your device, as well as giving the ability to view the live readings and status output on your laptop or mobile device.

Configuring your device

The main page has buttons to reach each area of configuration:

• Config — all general device and output settings. See the Configuration reference for the full list of options, value ranges and defaults.
• NTP Config — time zone and NTP server settings. See NTP Configuration.
• HV Config — high-voltage tuning for ESPGeiger-HW boards. See HV Configuration.

Console log

The Status page includes a live console tail of the device’s log. Timestamps follow two formats:

• HH:MM:SS — wall-clock time (device has synced to NTP and applied its configured timezone). The web UI converts these to your browser’s local timezone so they line up with the graph.
• HH:MM:SS* — uptime since boot. The trailing asterisk signals that NTP hasn’t synced yet; the time is not wall-clock and the browser should not timezone-shift it. Once NTP syncs, new lines appear without the asterisk.

In offline mode there is no wall-clock and no asterisk — timestamps are plain uptime. The web portal itself isn’t reachable when WiFi is disabled, but the same format appears on the serial console.

HTTP endpoints

The ESPGeiger web portal exposes a number of HTTP endpoints that are useful for integration, scripting, or simply linking to directly from a browser.

Path	Description
/	Main home page
/status	Detailed device status page (live readings, uptime, build info)
/hist	Rolling CPM history view
/json	Machine-readable status snapshot — see JSON Endpoint
/lastdata	GeigerLog-compatible CSV line — see GeigerLog
/about	Build, hardware and module identity (useful for support / debugging) — see below
/outputs	State of the configured third-party output modules — see below
/ntp	NTP configuration page
/hv	High-voltage tuning page (ESPGeiger-HW builds only)
/cpm?v=N	Set target CPM on test geiger builds — see Test build CPM setter
/restart	Reboots the device — use with care

For the /json response schema and examples of integrating /json or /lastdata with external tools (GeigerLog, Home Assistant, Prometheus, InfluxDB, Node-RED, Grafana), see Integrations.

/outputs response

Returns a JSON object keyed by module name, describing the state of each configured third-party output. Only modules that are enabled in the Config page appear — unconfigured or disabled modules are omitted. An empty object {} means no third-party outputs are active.

Possible keys: mqtt, radmon, thingspeak, gmc, webhook.

Example:

{
  "mqtt":       {"ok":true,  "age":42},
  "radmon":     {"ok":true,  "age":17},
  "thingspeak": {"ok":false, "age":91},
  "gmc":        {"ok":true,  "age":230},
  "webhook":    {"ok":false, "age":null}
}

Field	Meaning
ok	true if the last submission was accepted by the remote service. For MQTT this reflects the live connection plus a successful recent publish.
age	Seconds since the last submission attempt completed, or null if the module is enabled but has not yet attempted a submission (e.g. just after boot).

This is intended as a lightweight health check — useful for local dashboards, scripts, or Home Assistant REST sensors that want to know whether a given remote integration is working without subscribing to MQTT or scraping the logs.

/about response

Static identity information about the device and firmware, plus the list of compiled-in modules. Useful for support tickets and remote inventory. Things that change at runtime (uptime, memory, RSSI) live in /json instead.

Example:

{
  "ver": "0.8.0",
  "git": "06a2d9d",
  "env": "espgeigerlog",
  "date": "Apr 15 2026 12:34:56",
  "chip": "ESP8266",
  "mac": "AABBCCDDEEFF",
  "host": "ESPGeiger-a1b2c3",
  "g_mod": "genpulse",
  "g_type": "pulse",
  "g_test": false,
  "g_pcnt": true,
  "modules": ["disp","neopx","button","ntp","mqtt","radmon","whook","sercmd","serout"]
}

Field	Meaning
ver	Firmware version (release)
git	Short git commit the firmware was built from
env	PlatformIO build environment name (e.g. espgeigerlog, esp32oled_pulse)
b_date	Build timestamp (compile-time __DATE__ __TIME__)
chip	Chip model reported by the framework (ESP8266 / ESP32 / ESP32-S2 etc.)
mac	Device MAC address
host	Configured hostname
g_mod	Geiger model name set by the build / config. For serial builds this identifies the protocol (GC10, GC10Next, MightyOhm, ESPG).
g_type	Counter input type: "pulse", "serial", or "none" (pure test build with no hardware input)
g_test	true if the build is a test / simulation variant (generates pulses internally)
g_pcnt	true if the build uses the ESP32 PCNT hardware counter for pulse counting (false on ESP8266 builds, and on ESP32 builds compiled with -D IGNORE_PCNT)
modules	List of module identifiers compiled into this firmware

Test build CPM setter

Test builds (any target whose GEIGER_TYPE has the test bit set, e.g. espgeigerlog_test, esp32_testpulse, espgeigerlite_testpulse) expose /cpm so you can steer the simulated counter from a browser or script. This is useful for exercising downstream integrations (MQTT, Thingspeak, alert thresholds, dashboards) without needing a radiation source.

GET /cpm?v=<target_cpm>

Parameter	Meaning
v	Target CPM. Must be a positive integer; values ≤ 0 are ignored.

The internal test counter retargets to generate pulses at the given rate (Poisson-distributed for pulse-type test builds). Response body is OK on success.

Example — set target to 150 CPM:

curl http://192.168.1.100/cpm?v=150

The endpoint is absent from non-test builds.