Home Assistant AddOn Modbus Proxy

August 9, 2026 ยท View on GitHub

Allows you to connect multiple clients to one single modbus server. Usally one modbus server only allows a single connection and denies any more clients.

The addon is only tested and compatible with hassio supervisor.

Installation

Open your Home Assistant instance and show the add add-on repository dialog with a specific repository URL pre-filled.

  • Add This Repository (Or click Button above)
  • Install ModBusProxy from the Add-On Store

Configuration

  • Stop all Clients that currently connect to the modbus server. The Server might need some time before another client (our proxy) can connect.
    • In case you are using solaredge-modbus in homeassistant you can change the server address here: /config/.storage/core.config_entries.
  • Before starting go to the configuration page and set the ip of your modbus server.
  • Start The Add-On
    • This may take a while on the first start as it builds the cointainer locally. If there is more interest ill switch to prebuild containters.
  • Configure Your Clients to connect to your HA IP and choosen port.
  • I recommend not to change the listenport in neither the network section nor the listenport.

Multiple upstream devices

You can proxy several modbus servers at once. Each device gets its own listen port. Add a devices list in the add-on configuration (YAML mode):

devices:
  - upstreamhost: 192.168.1.212
    upstreamport: 502
    listenport: 502
  - upstreamhost: 192.168.1.213
    upstreamport: 502
    listenport: 503
    timeout: 5            # optional, overrides the global timeout
    connection_time: 0.5  # optional, overrides the global connection_time
loglevel: INFO

Notes:

  • When the devices list is set, the single device options (upstreamhost, upstreamport, listenport) are ignored. Without a devices list the add-on behaves exactly as before.
  • Each listenport must be unique and must also be enabled in the Network section of the add-on. Ports 502 to 510 are available there; map each one you use to the same number as the listenport of the device.

Configuration Tab

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Output after Start

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Mentions

This addon uses the modbus-proxy of tiagocoutinho:

Contribution

  • Multi-Device Support by @jomach