A gateway that bridges Fronius solar inverters to an MQTT broker using the Homie convention. Part of the @grovekit ecosystem.

homie-fronius periodically polls the local HTTP API of a Fronius inverter, reads real-time power flow data (solar production, grid import/export, battery charge/discharge, household consumption), and publishes it as a Homie device over MQTT.

Configuration is provided through environment variables.

HOMIE_URL=mqtt://localhost:1883
HOMIE_PREFIX=homie
FRONIUS_URL=http://192.168.1.42
LOG_LEVEL=info
POLLING_INTERVAL=10

On startup the gateway queries the Fronius API for available devices and registers a Homie root device named fronius-<device-id>. The device exposes the following nodes and properties:

fronius-<id>/
├── accumulator/            # Battery / accumulator
│   ├── power-charging      # float, W – power flowing into the battery
│   └── power-discharging   # float, W – power flowing out of the battery
├── grid/                   # Utility grid connection
│   ├── power-import        # float, W – power drawn from the grid
│   └── power-export        # float, W – power fed into the grid
├── load/                   # Household consumption
│   └── power-consumption   # float, W – power consumed by the household
└── pv/                     # Photovoltaic array
    └── power-production    # float, W – power produced by the PV array

All properties are read-only, retained, and expressed in watts (W).

The recommended way to run homie-fronius is via Docker Compose.

Create an .env file next to docker-compose.yml with your configuration, then start the service:

docker compose up -d

The gateway consumes the following endpoints from the Fronius local API:

• <FRONIUS_URL>/status/devices — lists available devices and their IDs
• <FRONIUS_URL>/status/powerflow — returns real-time power flow data

This project uses a total of 19 run-time dependencies and 41 dependencies in total, including both direct and indirect dependencies.

MIT © Jacopo Scazzosi