MeshCore/MQTT_IMPLEMENTATION.md

# MQTT Bridge Implementation for MeshCore

This document describes the MQTT bridge implementation that allows MeshCore repeaters to uplink packet data to multiple MQTT brokers.

## Quick Start Guide

**Prerequisites:** a MeshCore device flashed with observer MQTT firmware, WiFi network
credentials, and console access — either serial (115200 baud) or repeater login via the
companion app.

### Essential Commands to Get MQTT Observer Running

**1. Flash the observer firmware to your device**

The easiest route is the [MeshCore Observer Flasher](https://observer.gessaman.com/) — pick
**MQTT Observer Firmware**, select your device, and flash from the browser (Chrome or Edge).
To build it yourself instead, use one of the observer build targets (e.g.
`heltec_v4_repeater_observer_mqtt`) — see [Build Configuration](#build-configuration).

After flashing, connect to the device console via serial (115200 baud) or repeater login.

**2. Configure radio settings**

If this is a fresh flash or full erase, configure your radio parameters first. These must match other nodes in your mesh:

```bash
set radio 910.525,62.5,7,5
set tx 22
```

Format: `set radio <freq_MHz>,<bw_kHz>,<sf>,<cr>`

**3. Configure device identity**

```bash
set name MyObserver
set mqtt.iata SEA
```

If migrating from an existing node (e.g., a Raspberry Pi gateway), restore the private key to keep the same identity:
```bash
set prv.key <your_64_hex_char_private_key>
```

**4. Configure WiFi credentials** (value is the rest of the line; do not use quotes — see [WiFi Commands](#wifi-commands))
```bash
set wifi.ssid YourWiFiNetwork
set wifi.pwd YourWiFiPassword
```

**5. (Optional) Choose which brokers to publish to**

Slots 1 and 2 default to Let's Mesh Analyzer US and EU. To add or change a broker, pick a
name from [Broker Presets](#broker-presets):
```bash
set mqtt3.preset meshmapper
```

**6. (Optional) Configure timezone**

```bash
set timezone America/New_York
```

Or use a plain offset as a fallback: `set timezone.offset -5`. Published timestamps are
always UTC either way — see [Timezone Commands](#timezone-commands).

**7. (Optional) Disable packet repeating**

If this observer is receive-only (e.g., using a PCB antenna in a location where repeating would be harmful), disable forwarding:
```bash
set repeat off
```

**8. Reboot to connect**
```bash
reboot
```

**9. Verify configuration**
```bash
get wifi.ssid
get wifi.status
get bridge.enabled
get mqtt.rx
get mqtt.tx
get mqtt.origin
get mqtt.iata
get mqtt1.preset
get mqtt2.preset
get mqtt3.preset
get mqtt.status
```

**That's it!** The device will now:
- Connect to WiFi automatically
- Start uplinking mesh packets to configured MQTT brokers
- By default, publish to Let's Mesh Analyzer US (slot 1) and EU (slot 2)
- Use device name as MQTT origin (set automatically)

---

## Overview

The MQTT bridge implementation provides:
- Up to 6 MQTT connection slots, each holding a built-in preset for a community broker or a custom broker of your own — see [Broker Presets](#broker-presets)
- Per-preset authentication over WSS, MQTT/TLS, or plain MQTT: Ed25519-signed JWT, fixed or per-slot username/password, or none — see [Authentication](#authentication)
- Automatic reconnection with exponential backoff
- JSON message formatting for status, packet, raw, and neighbors data
- Packet queuing during connection issues
- Automatic migration from old configuration format

## Broker Presets

Each of the 6 slots holds one preset. Point a slot at a community broker with:

```bash
set mqtt3.preset meshmapper    # slot 3 → MeshMapper
```

Most presets need nothing else — the broker address, transport, and credentials all ship
in the firmware. The **Extra setup** column below lists the exceptions. Presets using the
`meshcore/{iata}/…` topic layout (every built-in except `meshrank`) also need `set mqtt.iata`.

Run `get mqtt.presets` on the device for the list this firmware actually ships; the table
below documents the current build.

| Preset | Broker | Auth | Extra setup |
|--------|--------|------|-------------|
| `analyzer-us` | `wss://mqtt-us-v1.letsmesh.net:443/mqtt` | JWT | — (default slot 1) |
| `analyzer-eu` | `wss://mqtt-eu-v1.letsmesh.net:443/mqtt` | JWT | — (default slot 2) |
| `nz-analyzer` | `wss://meshcore-mqtt-1.baird.io:443` | JWT | — |
| `meshmapper` | `wss://mqtt.meshmapper.net:443/mqtt` | JWT | — |
| `meshrank` | `mqtts://meshrank.net:8883` | None (token in topic) | `set mqttN.token <token>` |
| `waev` | `wss://mqtt.waev.app:443/mqtt` | JWT | — |
| `meshomatic` | `wss://us-east.meshomatic.net:443/mqtt` | JWT | — |
| `cascadiamesh` | `wss://mqtt-v1.cascadiamesh.org:443/mqtt` | JWT | — |
| `tennmesh` | `mqtt://mqtt.tennmesh.com:1883` | User/pass (in firmware) | — |
| `nashmesh` | `mqtt://mqtt.nashme.sh:1883` | User/pass (in firmware) | — |
| `ctmesh` | `mqtt://mqtt.ctmesh.org:1883` | User/pass (in firmware) | — |
| `chimesh` | `wss://mqtt.chimesh.org:443` | JWT | — |
| `meshat.se` | `wss://meshcore-mqtt.meshat.se:443` | JWT | — |
| `eastidahomesh` | `mqtt://live.eastidahomesh.com:1883` | None | — |
| `coloradomesh` | `wss://mqtt.meshcore.coloradomesh.org:443` | JWT | — |
| `dutchmeshcore-1` | `wss://collector1.dutchmeshcore.nl:443/mqtt` | JWT | — |
| `dutchmeshcore-2` | `wss://collector2.dutchmeshcore.nl:443/mqtt` | JWT | — |
| `meshcore-ca-1` | `wss://mqtt1.meshcore.ca:443/mqtt` | JWT | — |
| `meshcore-ca-2` | `wss://mqtt2.meshcore.ca:443/mqtt` | JWT | — |
| `meshcore-fi` | `wss://mc-mqtt.meshcore.fi:443/` | JWT | — |
| `inwmesh` | `mqtts://scope.inwmesh.org:8883` | User/pass (per slot) | `set mqttN.username` + `set mqttN.password` |
| `bostonmesh` | `wss://mqttmc01.bostonme.sh:443/mqtt` | JWT | — |
| `rflab` | `wss://mqtt.rflab.io:443` | JWT | — |
| `ipnt.uk` | `wss://mqtt.ipnt.uk:443` | JWT | — |
| `flmesh` | `wss://mcmqtt.jntconnections.com:443` | JWT | — |
| `corecomms` | `wss://mqtt.corecomms.net:443/mqtt` | JWT | — |
| `meshtexas` | `wss://mqtt.meshtexas.org:443/mqtt` | JWT | — |
| `mesh-chaun14` | `mqtt://mqtt.mesh.chaun14.fr:1884` | User/pass (username is the device public key) | `set mqttN.password` |
| `wcmesh` | `wss://mqtt.wcmesh.com:443` | JWT | — |
| `custom` | your own broker | User/pass, or JWT when `mqttN.audience` is set | `set mqttN.server` (see [custom broker setup](#custom-brokers)) |
| `none` | (slot disabled) | — | — |

Transport is the URL scheme: `wss://` is WebSocket Secure, `mqtts://` is MQTT over TLS,
and `mqtt://` is plain unencrypted MQTT. The two TLS schemes are what count against the
non-PSRAM slot limit below.

### Slots and Memory Limits

Fresh installs default to slot 1 `analyzer-us`, slot 2 `analyzer-eu`, and slots 3–6 `none`.

- **With PSRAM:** all 6 slots can be active simultaneously
- **Without PSRAM:** maximum 2 active TLS/WSS slots (each WSS/TLS connection requires ~40KB internal heap)
- Slots configured beyond what the device supports show as `(inactive)` in `get mqtt.status`
- Slot configuration is preserved in preferences — moving the firmware to a PSRAM device activates the rest

## Build Configuration

To build the MQTT bridge firmware:

```bash
# Heltec V3
pio run -e Heltec_v3_repeater_observer_mqtt

# Heltec V4
pio run -e heltec_v4_repeater_observer_mqtt

# Heltec Wireless Tracker v1.1 / v2
pio run -e heltec_tracker_v1_1_repeater_observer_mqtt
pio run -e heltec_tracker_v1_1_room_server_observer_mqtt
pio run -e heltec_tracker_v2_repeater_observer_mqtt
pio run -e heltec_tracker_v2_room_server_observer_mqtt

# Station G2
pio run -e Station_G2_repeater_observer_mqtt

# Station G3 (ESP32)
pio run -e Station_G3_ESP32_repeater_observer_mqtt
pio run -e Station_G3_ESP32_room_server_observer_mqtt

# LilyGo T-LoRa V2.1-1.6 (TTGO LoRa32 V1.0)
pio run -e LilyGo_TLora_V2_1_1_6_repeater_observer_mqtt
pio run -e LilyGo_TLora_V2_1_1_6_room_server_observer_mqtt
```

**TLora naming:** The env prefix `LilyGo_TLora_V2_1_1_6` is LilyGo’s **T-LoRa V2.1–1.6** board (SX1276); PlatformIO selects **`ttgo-lora32-v1`** (TTGO LoRa32 V1.0). **MQTT observer** envs extend a slim base **without** `sensor_base` so the image fits `min_spiffs`; **all other** `LilyGo_TLora_V2_1_1_6_*` targets still use optional I2C environmental sensors as before. The **`lilygo_tlora_c6`** variant is separate hardware (ESP32-C6).

**T-LoRa V2.1–1.6 MQTT observer — one WSS broker:** This hardware is **classic ESP32 without PSRAM**. Each WSS preset uses a full TLS stack and large contiguous heap allocations; **two active broker presets at once** typically fails the second connection (`mbedtls_ssl_setup` / `esp-tls` `0x8017`, low `IntMax` in `memory`). **Treat these observer builds as supporting one active cloud preset:** configure the broker you need in `mqtt1` or `mqtt2`, and set the other slot to `none` (e.g. `set mqtt2.preset none`). Use PSRAM-capable boards if you need multiple simultaneous MQTT uplinks.

### Partition Table Changes — Merged Firmware Required

Some MQTT observer builds use a non-default partition table to accommodate the larger firmware size (MQTT libraries, TLS, cert bundle, etc.). **When a board's partition table changes, you must flash the merged firmware (`*-merged.bin`) the first time** so the new partition layout and bootloader are written together. After that initial flash, standard OTA or non-merged updates will work normally.

| Environment | Partition Table | Flash Size | App Slot Size | Notes |
|-------------|----------------|------------|---------------|-------|
| `LilyGo_T3S3_sx1262_repeater_observer_mqtt` | `min_spiffs.csv` | 4 MB | 1.875 MB | Changed from default (1.25 MB) |
| `LilyGo_T3S3_sx1262_room_server_observer_mqtt` | `min_spiffs.csv` | 4 MB | 1.875 MB | Changed from default (1.25 MB) |
| `LilyGo_TLora_V2_1_1_6_repeater_observer_mqtt` | `min_spiffs.csv` | 4 MB | 1.875 MB | TTGO LoRa32 V1.0; observer omits `sensor_base`. See the one-WSS-broker note above. |
| `LilyGo_TLora_V2_1_1_6_room_server_observer_mqtt` | `min_spiffs.csv` | 4 MB | 1.875 MB | same |
| `Station_G2_repeater_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | 16 MB flash board |
| `Station_G2_room_server_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | 16 MB flash board |
| `Station_G3_ESP32_repeater_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | 16 MB flash board |
| `Station_G3_ESP32_room_server_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | 16 MB flash board |
| `LilyGo_TBeam_1W_repeater_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | Set in `boards/t_beam_1w.json`; required vs implicit `default.csv` |
| `LilyGo_TBeam_1W_room_server_observer_mqtt` | `default_16MB.csv` | 16 MB | 6.25 MB | same |

**Settings loss when the layout changes**

A merged image writes a new bootloader **and** partition table at offset `0x0`. If that
layout differs from what the device already has, **NVS is typically wiped** — expect to lose
stored configuration (admin preferences, WiFi, MQTT slots, name) and reconfigure from
scratch. If the layout is unchanged, NVS is usually retained, though Bluetooth pairings may
still be cleared on some upgrade paths.

Two cases catch people out: the TLora observer builds use the same `min_spiffs.csv` as other
MeshCore TLora builds, so normal repeater ↔ room server ↔ observer moves are fine — but
coming *from* an older TLora observer that used `huge_app.csv` is a layout change. And any
device previously running a non-MeshCore partition map will be wiped by its first merged
flash regardless of target.

**How to flash the merged firmware:**

- **Web flasher (recommended):** Use the [MeshCore Observer Flasher](https://observer.gessaman.com/) to flash from your browser — no tools to install. Pick **MQTT Observer Firmware** and your device. Its Download menu also serves the individual `*-merged.bin`, erase, and bootloader files if you would rather flash with something else. Requires Chrome or Edge.
- **Command line:**
  ```bash
  # Build the merged binary
  pio run -t mergebin -e LilyGo_T3S3_sx1262_repeater_observer_mqtt

  # Flash at offset 0x0 (overwrites bootloader + partition table)
  esptool.py write_flash 0x0 .pio/build/LilyGo_T3S3_sx1262_repeater_observer_mqtt/firmware-merged.bin
  ```

### Build Flags
- `WITH_MQTT_BRIDGE=1` - Enable MQTT bridge (required)
- `WITH_SNMP=1` - Enable SNMP agent (optional, see [MQTT_SNMP.md](MQTT_SNMP.md))
- `MQTT_DEBUG=1` - Enable debug logging (optional)
- `MQTT_WIFI_TX_POWER` - WiFi TX power level (default: `WIFI_POWER_11dBm`)
- ~~`MQTT_WIFI_POWER_SAVE_DEFAULT`~~ - Removed; all builds now default to `none` (no power save)

#### Compile-time fresh-install defaults (`src/helpers/MQTTDefaults.h`)

Optional PlatformIO `build_flags` override defaults written when `/mqtt_prefs` is first created. They do **not** change existing saved prefs on upgrade or reflash (unless `/mqtt_prefs` is erased).

| Macro | Default | Notes |
|-------|---------|-------|
| `MQTT_DEFAULT_SLOT1_PRESET` … `MQTT_DEFAULT_SLOT6_PRESET` | slots 1–2: `analyzer-us` / `analyzer-eu`; slots 3–6: `none` | Must be a built-in preset name, `none`, or `custom` |
| `MQTT_DEFAULT_IATA` | (empty) | e.g. `'"YYZ"'` |
| `MQTT_DEFAULT_TIMEZONE` | (empty) | e.g. `'"America/Toronto"'` |
| `MQTT_DEFAULT_TIMEZONE_OFFSET` | `0` | Fallback hours when TZ string is empty |

Example community build:

```ini
build_flags =
  -D MQTT_DEFAULT_SLOT1_PRESET='"meshcore-ca-1"'
  -D MQTT_DEFAULT_SLOT2_PRESET='"meshcore-ca-2"'
  -D MQTT_DEFAULT_IATA='"YYZ"'
  -D MQTT_DEFAULT_TIMEZONE='"America/Toronto"'
  -D MQTT_DEFAULT_TIMEZONE_OFFSET=-5
```

WiFi SSID/password are not compile-time configurable (operators set them per device via CLI).

Legacy `get mqtt.analyzer_us` / `set mqtt.analyzer_us` still refer to the preset name `analyzer-us`, not “whatever slot 1 default is”.

## Default Configuration

The MQTT bridge comes with the following defaults for fresh installs (unless overridden by the macros above):
- **Origin**: Device name (set automatically from `set name`)
- **IATA**: (blank — must be configured for MeshCore-style topic presets such as Analyzer and TennMesh, unless `MQTT_DEFAULT_IATA` is set at build time)
- **Status Messages**: Enabled
- **Packet Messages**: Enabled
- **Raw Messages**: Disabled
- **RX Packets**: Enabled (uplink received packets)
- **TX Packets**: `advert` by default (uplink this node's own adverts; set to `on` for all TX or `off` to disable)
- **Status Interval**: 5 minutes (300000 ms)
- **Slot 1**: `analyzer-us`
- **Slot 2**: `analyzer-eu`
- **Slots 3-6**: `none` (disabled)
- **WiFi SSID**: (blank — must be configured)
- **WiFi Password**: (blank — optional for open networks)
- **WiFi Power Save**: `none` (no power save)
- **Timezone**: (blank — uses UTC until configured, unless `MQTT_DEFAULT_TIMEZONE` is set at build time)
- **Timezone Offset**: 0 (fallback, no offset, unless `MQTT_DEFAULT_TIMEZONE_OFFSET` is set)
- **Repeat (forwarding)**: On (set `repeat off` for receive-only observers)

## CLI Commands

### MQTT Slot Commands

Each slot (1-6) supports the following commands:

#### Get Commands
- `get mqtt1.preset` - Get slot 1 preset name
- `get mqtt2.preset` - Get slot 2 preset name
- `get mqttN.preset` - Get slot N preset name (N = 1-6)
- `get mqttN.server` - Get custom server hostname for slot N
- `get mqttN.port` - Get custom server port for slot N
- `get mqttN.username` - Get custom username for slot N
- `get mqttN.password` - Get custom password for slot N
- `get mqttN.token` - Get per-slot token (e.g., MeshRank account token)
- `get mqttN.topic` - Get custom topic template for slot N
- `get mqttN.audience` - Get JWT audience for slot N (custom slots only)

#### Set Commands
- `set mqttN.preset <name>` - Set slot N to a built-in preset. Use any `name` from [Broker Presets](#broker-presets), which also lists the few presets needing extra setup.
- `set mqttN.preset custom` - Set slot N to custom broker (configure server/port/username/password)
- `set mqttN.preset none` - Disable slot N
- `set mqttN.server <hostname>` - Set custom server hostname for slot N
- `set mqttN.port <port>` - Set custom server port for slot N (1-65535)
- `set mqttN.username <username>` - Set username for slot N (`custom` preset, or presets like `inwmesh` that require per-device credentials)
- `set mqttN.password <password>` - Set password for slot N (`custom` preset, or presets like `inwmesh` that require per-device credentials)
- `set mqttN.token <token>` - Set per-slot token (required for MeshRank preset)
- `set mqttN.topic <template>` - Set custom topic template (custom preset only, see below)
- `set mqttN.audience <audience>` - Set JWT audience for custom slot (enables Ed25519 JWT auth)
- `set mqttN.audience` - Clear JWT audience (reverts to username/password auth)

**Note:** Custom server/port settings only apply when the slot's preset is `custom`. Username/password also apply to built-in presets that use per-slot credentials (e.g. `inwmesh`); other userpass presets (`tennmesh`, `nashmesh`, `ctmesh`) ship fixed credentials in firmware.

#### Example: MeshRank

MeshRank needs an account token, generated on the MeshRank website and tied to your account:
```bash
set mqtt3.preset meshrank
set mqtt3.token FE1B34242C5938C39225310081FD6718
```

It receives the same message types as any other preset (`status`, `packets`, `raw`,
`neighbors`), each under `meshrank/uplink/{token}/{device_id}/`, subject to the usual
`mqtt.status` / `mqtt.raw` / `mqtt.neighbors` toggles. Its broker does not accept the retain
flag, so those publishes go out unretained.

### Custom Brokers

Set the preset to `custom` and supply the broker address, plus credentials in whichever style
the broker expects.

**Username/password:**
```bash
set mqtt3.preset custom
set mqtt3.server your-broker.example.com
set mqtt3.port 1883
set mqtt3.username your-username
set mqtt3.password your-password
```

**Ed25519 JWT** — for community brokers implementing the same JWT auth protocol as the
built-in presets. Setting `audience` is what switches the slot to JWT:
```bash
set mqtt3.preset custom
set mqtt3.server wss://my-broker.example.com:443/mqtt
set mqtt3.audience my-broker.example.com
```

With `audience` set, the device connects as `v1_{PUBLIC_KEY}` with an Ed25519-signed JWT as
the password, renews tokens before expiry (default 24h lifetime), and includes the owner
public key and email in the JWT payload if `set mqtt.owner` / `set mqtt.email` are
configured. Clear it with a bare `set mqtt3.audience` to revert to username/password.

**Local development broker** — a LAN broker with no SSL termination. Non-TLS transports
(`ws://`, `mqtt://`) skip certificate verification entirely:
```bash
set mqtt3.preset custom
set mqtt3.server ws://192.168.1.50:9001/mqtt
```

**Custom topic layout** — see [Custom Topic Templates](#custom-topic-templates) below:
```bash
set mqtt3.topic mynetwork/{device}/{type}
```

When the server is given as a full URL with a scheme (`mqtt://`, `mqtts://`, `ws://`,
`wss://`), `set mqttN.port` is optional — an explicit port in the URL is used as-is, and
without one the scheme's default port applies.

### Custom Topic Templates

When a slot's preset is `custom`, you can define a custom topic template using placeholders:

| Placeholder | Value | Example |
|-------------|-------|---------|
| `{iata}` | IATA airport code | `SEA` |
| `{device}` | Device public key (64 hex chars) | `CC5D3CFD...` |
| `{token}` | Per-slot token from `mqttN.token` | `FE1B3424...` |
| `{type}` | Message type | `status`, `packets`, or `raw` |

If no custom topic is set, custom slots default to: `meshcore/{iata}/{device}/{type}`

**Note:** Topic templates only apply to `custom` preset slots. Built-in presets (analyzer-us, analyzer-eu, meshmapper, meshrank, eastidahomesh, coloradomesh, tennmesh, etc.) always use their hardcoded topic format.

### MQTT Shared Commands

These settings apply across all MQTT slots:

#### Get Commands
- `get mqtt.origin` - Get device origin name
- `get mqtt.iata` - Get IATA code
- `get mqtt.presets` - List available MQTT presets (paginated, comma-separated)
- `get mqtt.presets <start>` - Continue list from index shown in `... next:<idx>`
- `get mqtt.status` - Get MQTT status summary (connection info per slot, plus the periodic neighbors schedule when `mqtt.neighbors` is on)
- `get mqtt.packets` - Get packet message setting (on/off)
- `get mqtt.raw` - Get raw message setting (on/off)
- `get mqtt.rx` - Get RX packet uplinking setting (on/off)
- `get mqtt.tx` - Get TX packet uplinking setting (on/off/advert)
- `get mqtt.interval` - Get status publish interval
- `get mqtt.neighbors` - Get periodic neighbors publish (PSRAM builds: on/off)
- `get mqtt.neighbors.interval` - Get neighbors publish interval in hours
- `get mqtt.ntp` - Get effective NTP server hostname
- `get mqtt.ntp.diag` - Probe every configured NTP server for connectivity (does not change the clock; serial console shows each server's reported time, LoRa shows a compact `<server> ok|fail` list)
- `get mqtt.owner` - Get owner public key (serial console only)
- `get mqtt.email` - Get owner email address (serial console only)

#### Set Commands
- `set mqtt.origin <name>` - Set device origin name
- `set mqtt.iata <code>` - Set IATA code (auto-uppercased)
- `set mqtt.status on|off` - Enable/disable status messages
- `set mqtt.packets on|off` - Enable/disable packet messages
- `set mqtt.raw on|off` - Enable/disable raw messages
- `set mqtt.rx on|off` - Enable/disable RX (received) packet uplinking
- `set mqtt.tx on|off|advert` - Set TX packet uplinking mode:
  - `on` - Uplink all transmitted packets
  - `advert` - Uplink only this node's own advert packets (self-originated)
  - `off` - Disable TX packet uplinking
- `set mqtt.interval <minutes>` - Set status publish interval (1-60 minutes)
- `set mqtt.neighbors on|off` - Enable/disable periodic neighbors/scopes publish (PSRAM builds only)
- `set mqtt.neighbors.interval <hours>` - Set neighbors publish interval (12-336 hours, default 24)
- `set mqtt.ntp <hostname>` - Set custom NTP server (validated with immediate sync); `none` reverts to default
- `set mqtt.owner <64-hex-char-public-key>` - Set owner public key
- `set mqtt.email <email>` - Set owner email address

### WiFi Commands

#### Get Commands
- `get wifi.ssid` - Get WiFi SSID
- `get wifi.pwd` - Get WiFi password
- `get wifi.status` - Get WiFi connection status, IP, RSSI, and uptime
- `get wifi.powersave` - Get WiFi power save mode (none/min/max)

#### Set Commands
- `set wifi.ssid <ssid>` - Set WiFi SSID
- `set wifi.pwd <password>` - Set WiFi password
- `set wifi.powersave none|min|max` - Set WiFi power save mode

> **Note:** The value is everything after the first space (spaces in SSID/password are fine). Do not wrap in quotes — they are stored literally. Max length: 31 characters (SSID), 63 (password). For open networks, use `set wifi.pwd ` with nothing after the space.
  - `none` - No power saving (best performance, highest power consumption)
  - `min` - Minimum power saving (balanced performance and power)
  - `max` - Maximum power saving (lowest power consumption, may affect performance)

### Timezone Commands

#### Get Commands
- `get timezone` - Get timezone string (e.g., "America/Los_Angeles")
- `get timezone.offset` - Get timezone offset in hours (-12 to +14)

#### Set Commands
- `set timezone <string>` - Set timezone string (IANA format or abbreviation)
- `set timezone.offset <offset>` - Set timezone offset in hours (-12 to +14)

#### Supported Timezone Formats
- **IANA strings**: `America/Los_Angeles`, `Europe/London`, `Asia/Tokyo`, etc.
- **Common abbreviations**: `PDT`, `PST`, `MDT`, `MST`, `CDT`, `CST`, `EDT`, `EST`, `BST`, `GMT`, `CEST`, `CET`
- **UTC offsets**: `UTC-8`, `UTC+5`, `+5`, `-8`, etc.

### Device & Radio Commands

These are standard MeshCore commands, not MQTT-specific, but important for observer setup:

#### Get Commands
- `get name` - Get device name
- `get repeat` - Get repeat (forwarding) status (on/off)
- `get freq` - Get radio frequency
- `get public.key` - Get device public key (for migration)

#### Set Commands
- `set name <name>` - Set device name (also sets MQTT origin)
- `set repeat on|off` - Enable/disable packet forwarding (use `off` for receive-only observers)
- `set prv.key <64-hex-char-key>` - Restore private key (for migrating identity from another device)
- `set tx <dBm>` - Set transmit power

### Bridge Commands

#### Get Commands
- `get bridge.source` - Get packet source (rx/tx)
- `get bridge.enabled` - Get bridge enabled status (on/off)

#### Set Commands
- `set bridge.source rx|tx` - Set packet source (rx for received, tx for transmitted)
- `set bridge.enabled on|off` - Enable/disable bridge

> **Note:** `bridge.enabled` is the master switch for the whole bridge system. `bridge.source`
> applies to non-MQTT bridges (RS232, ESP-NOW) only — for MQTT use `mqtt.rx` and `mqtt.tx`,
> which control each direction independently.

### SNMP Commands

Observer nodes include an optional SNMP v2c agent that exposes radio stats, MQTT
connectivity, memory usage, and network information to standard monitoring tools.

#### Get Commands
- `get snmp` - Get SNMP agent status (on/off)
- `get snmp.community` - Get SNMP community string

#### Set Commands
- `set snmp on|off` - Enable/disable SNMP agent (restart required)
- `set snmp.community <string>` - Set SNMP community string (restart required, default: `public`)

See [MQTT_SNMP.md](MQTT_SNMP.md) for setup and the full OID reference.

## MQTT Topics

The bridge publishes to four main topics with the following structure:

### Status Topic: `meshcore/{IATA}/{DEVICE_PUBLIC_KEY}/status`
Device connection status and metadata, QoS 1. Retained, except on presets whose broker rejects the retain flag (`meshrank`, `waev`).

### Packets Topic: `meshcore/{IATA}/{DEVICE_PUBLIC_KEY}/packets`
Full packet data with RF characteristics and metadata.

### Raw Topic: `meshcore/{IATA}/{DEVICE_PUBLIC_KEY}/raw`
Minimal raw packet data for map integration.

### Neighbors Topic: `meshcore/{IATA}/{DEVICE_PUBLIC_KEY}/neighbors`
Cached zero-hop repeater neighbors with SNR, last-heard age, and flood-allowed scopes. Published on `discover.scopes` or periodically when `mqtt.neighbors` is enabled (PSRAM observer builds only). Goes to every configured slot's `neighbors` topic at QoS 1, retained only where the preset allows it.

Periodic publishing first runs a 60-second zero-hop neighbor refresh equivalent to `discover.neighbors`, then queries the refreshed table for scopes and publishes when the scope-query phase completes.

Manual `discover.scopes` normally queries the current cache in one shot. If a `discover.neighbors` refresh is already collecting responses — whether started from the CLI or by the periodic timer — the scope queries are queued behind its 60-second window instead, so they run against the refreshed table. The reply reports the wait, e.g. `OK - scopes queued (47s discovery remaining)`. A queued one-shot request survives `set mqtt.neighbors off`; only the periodic timer's own refresh is cancelled by it.

While `mqtt.neighbors` is on, `get mqtt.status` appends `nbr: <next>/<last>` — time to the next automatic publish (`3h12m`, `12m`, `45s`, or `active`/`due`) and the last publish result (`ok`, `failed`, or `none`).

**Note**: `{DEVICE_PUBLIC_KEY}` is the device's public key in hexadecimal format (64 characters). MeshRank slots use `meshrank/uplink/{token}/{DEVICE_PUBLIC_KEY}/neighbors` instead.

## JSON Message Formats

### Status Message
```json
{
  "status": "online|offline",
  "timestamp": "2024-01-01T12:00:00.000000+00:00",
  "origin": "Device Name",
  "origin_id": "DEVICE_PUBLIC_KEY",
  "model": "device_model",
  "firmware_version": "firmware_version",
  "radio": "radio_info",
  "client_version": "meshcore/{firmware_version}",
  "repeat": "on|off",
  "stats": {
    "battery_mv": 4100,
    "uptime_secs": 3600,
    "packets_sent": 42,
    "packets_received": 128,
    "errors": 0,
    "queue_len": 0,
    "noise_floor": -110,
    "tx_air_secs": 12,
    "rx_air_secs": 340,
    "recv_errors": 2,
    "internal_heap": 102400
  }
}
```

**Notes:**
- Timestamps are always emitted in UTC with an explicit `+00:00` offset.
- The `stats` object is only included when at least one stat value is available; individual fields are omitted when their value is unavailable.
- `packets_sent` / `packets_received` are cumulative totals since boot (flood + direct), sourced from the dispatcher counters.

### Packet Message
```json
{
  "origin": "MeshCore-HOWL",
  "origin_id": "A1B2C3D4E5F67890...",
  "timestamp": "2024-01-01T12:00:00.000000+00:00",
  "type": "PACKET",
  "direction": "rx|tx",
  "time": "12:00:00",
  "date": "01/01/2024",
  "len": "45",
  "packet_type": "4",
  "route": "F|D|T|U",
  "payload_len": "32",
  "raw": "F5930103807E5F1E...",
  "SNR": "12.5",
  "RSSI": "-65",
  "score": "234",
  "hash": "A1B2C3D4E5F67890",
  "path": ["aa", "bb", "cc"]
}
```

**Notes:**
- All numeric fields (`len`, `packet_type`, `payload_len`, `SNR`, `RSSI`, `score`) are formatted as JSON strings.
- `time` and `date` are always UTC (`HH:MM:SS` and `DD/MM/YYYY`); `timestamp` is UTC with an explicit `+00:00` offset.
- `SNR`, `RSSI`, and `score` are only present for RX packets (received from radio). TX packets omit these fields since the packet originates from this node.
- `score` is the firmware's rebroadcast score for the received packet (the same value used to compute flood-rebroadcast delay), scaled ×1000 to match the integer printed in the serial RX log — e.g. a score of `0.234` is emitted as `"234"` (range `0`–`1000`). Omitted when unavailable (e.g. the non-PSRAM reconstruction-less fallback path).
- `path` is only present for direct-route packets that carry path data. It is a JSON array of lowercase hex hop tokens, one element per hop — e.g. `["aa","bb","cc"]` for single-byte hashes, or `["aaaa","bbbb"]` for multi-byte hashes. This matches the `path` representation emitted by [meshcore-packet-capture](https://github.com/agessaman/meshcore-packet-capture).

### Raw Message
```json
{
  "origin": "MeshCore-HOWL",
  "origin_id": "A1B2C3D4E5F67890...",
  "timestamp": "2024-01-01T12:00:00.000000+00:00",
  "type": "RAW",
  "data": "F5930103807E5F1E..."
}
```

### Neighbors Message (PSRAM observer builds)
```json
{
  "timestamp": "2026-06-07T12:00:00.000000+00:00",
  "origin": "MQTT Observer",
  "origin_id": "DEVICE_PUBLIC_KEY",
  "self": {
    "scopes": "Europe,UK,France"
  },
  "neighbors": [
    {
      "pubkey": "NEIGHBOR_PUBLIC_KEY",
      "snr": 8.5,
      "heard_secs_ago": 120,
      "scopes": "*,Europe",
      "status": "responded"
    }
  ]
}
```

**Notes:**
- `status` per neighbor: `responded`, `timeout`, or `send_failed` (scope query only; `self` has no status field).
- Trigger with `discover.scopes` or enable periodic publish via `set mqtt.neighbors on`.

## Key Features

### Connection Handling
- Automatic reconnection with exponential backoff per slot; a slot that stays down through
  the full backoff ladder is retried on a slow periodic probe instead of hammering the broker
- Packets are queued while a slot is disconnected and flushed when it recovers

### Raw Radio Data Capture
- Captures actual raw radio transmission data (including radio headers)
- Provides accurate SNR/RSSI values from actual radio reception (RX packets only)
- Independent RX and TX packet uplinking — both can be active simultaneously
- TX advert mode: selectively uplink only this node's own advert packets

### Timezone Support
- Accepts IANA timezone strings, common abbreviations, and UTC offsets, with automatic DST handling
- Note: all published MQTT timestamps are UTC regardless of the configured timezone

### WiFi Configuration
- Runtime WiFi credential management via CLI
- Persistent storage across reboots
- Automatic reconnection with exponential backoff

### NTP Time Synchronization
- Automatic time synchronization with NTP servers (required for JWT authentication)
- Default primary: `pool.ntp.org`; built-in fallbacks (tried sequentially on failure): `time.google.com`, `time.cloudflare.com`, `time.aws.com`, `time.nist.gov`
- Periodic time updates (every hour) on the effective primary only; system time is kept in UTC
- Configure and diagnose with `set mqtt.ntp` / `get mqtt.ntp` / `get mqtt.ntp.diag` — see [MQTT Shared Commands](#mqtt-shared-commands)

### Authentication
The auth mode is fixed per preset (see [Broker Presets](#broker-presets)). Three modes are used:
- **JWT Authentication**: Ed25519-signed tokens for brokers that expect JWT (most WSS presets). For `custom` slots, JWT is used when `audience` is set.
- **Username/Password**: Some presets ship fixed credentials embedded in firmware (`tennmesh`, `nashmesh`, `ctmesh` — plain MQTT, no TLS); others (`inwmesh`, `custom`) take per-slot credentials via `mqttN.username` / `mqttN.password`.
- **None**: `meshrank` (account token carried in the topic) and `eastidahomesh` connect without broker auth.
- **Username Format** (JWT): `v1_{UPPERCASE_PUBLIC_KEY}`
- **Automatic Token Renewal**: Tokens are renewed before expiration

## Migration from Old Configuration

Upgrading from firmware that used an older settings layout — including the pre-slot format
(`mqtt.analyzer.us`, `mqtt.server`, …) — needs no manual intervention: the device converts
its stored configuration on the first boot after the update and keeps your brokers, origin,
IATA, message types, WiFi, and timezone. Verify with `get mqtt.status` afterwards.

The one exception is firmware old enough to predate the separate observer settings file: on
that upgrade path the MQTT slot and WiFi configuration cannot be recovered and must be
re-entered. For the per-format details, see
[MQTT_INTERNALS.md](MQTT_INTERNALS.md#settings-upgrade--migration).

## Troubleshooting

#### Device Won't Connect to WiFi
```
get wifi.ssid
get wifi.pwd
set wifi.powersave none    # Try disabling power saving
reboot
```

#### No MQTT Messages Appearing
```
get bridge.enabled
set bridge.enabled on
get mqtt.rx                # Should be "on"
set mqtt.rx on
get mqtt.status            # Check per-slot connection status
get mqtt1.diag             # Last slot error details (TLS/sock/time)
get mqtt2.diag
get mqtt3.diag
get mqtt1.preset           # Verify slots are configured
get mqtt.iata              # IATA must be set for MeshCore-topic presets (e.g. Analyzer, ColoradoMesh, TennMesh)
```

#### Timezone Issues
```
get timezone
get timezone.offset
```
See [Supported Timezone Formats](#supported-timezone-formats) for the accepted values.
Note that published timestamps are UTC regardless of this setting.

## Fault Alerts

Fault alerts broadcast LoRa group-channel notifications when WiFi or configured MQTT links stay down past configured thresholds, with optional recovery notices and rate limiting to avoid spam.
For configuration, CLI commands, examples, and operational notes, see [ALERTS.md](ALERTS.md).

## Radio Watchdog

The radio watchdog detects a LoRa radio that appears stuck in RX mode but has stopped seeing any activity (valid packets, radio interrupts, or successful TX). When the configured silence interval is exceeded, the firmware idles the radio and restarts receive mode. This helps long-running MQTT observers recover from conditions such as PSRAM starvation that can cause missed radio interrupts without a full reboot.

Activity is tracked from the most recent of: a valid RX, any radio ISR (including CRC errors), or a successful TX. That composite timestamp reduces false recoveries on quiet meshes where legitimate packet gaps can exceed the watchdog interval.

#### Get Commands
- `get radio.watchdog` - Get watchdog interval in minutes (`0` = disabled)

#### Set Commands
- `set radio.watchdog <minutes>` - Set watchdog interval (`0` to disable, or `1-120`)

**Default:** `5` minutes

**Examples:**
```bash
get radio.watchdog
set radio.watchdog 10    # 10-minute silence before recovery
set radio.watchdog 0     # disable watchdog
```

On very quiet meshes where no traffic is expected for long periods, increase the interval or set `0` to disable the watchdog and avoid unnecessary radio recoveries.

## Developer Documentation

For source layout, the seams that isolate the observer feature from upstream MeshCore code, and on-device settings migration across firmware versions, see [MQTT_INTERNALS.md](MQTT_INTERNALS.md).