Post to Mastodon from Home Assistant in 2025

Home Assistant will no longer be supporting notify.mastodon_notify from September 2025. There is a new action mastodon.post and also config_entry_id: which uses the MASTODON_CONFIG_ENTITY_ID.

The Home Assistant documentation can be found here.

The issue I had was finding the MASTODON_CONFIG_ENTITY_ID. In the guide it says use the Developer Tools and using one of the actions. This is how to find the MASTODON_CONFIG_ENTITY_ID.

Go to the Developer Tool menu and then the Actions. Choice Mastodon: Post as the Action and mastodon_notify as the Mastodon account. Add status to the Status option. Then click perform action at the bottom of the page. You should see a green tick and then it will go back to perform action.

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Home Assistant Developer Tool Action Menu

Now click on Go To YAML at the bottom of the page and you will see the MASTODON_CONFIG_ENTITY_ID for your account

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MASTODON_CONFIG_ENTITY_ID. is shown in the YAML

Here is one of my Mastodon notifications. This one post the Solcast forecast at 8.30am each morning

alias: Mastodon Solcast Forecast v2025.1
description: Mastodon Solcast Forecast v2025.1. Uses integration
triggers:
  - at: "8:30:00"
    trigger: time
conditions: []
actions:
  - data:
      config_entry_id: 1234567890
      status: |
        Solcast forecast for today (South East 4x400w panels) - 

          {{states("sensor.front_panels_se") | round(2) }} kWh


          Solcast forecast for today (East 4x400w panels) - 

          {{states("sensor.front_panels_east") | round(2)}} kWh


          Solcast forecast for today (West North 6x400w panels) - 

          {{states("sensor.back_panels_west_north") | round(2)}} kWh


          Solcast forcasting a total of {{
          states("sensor.solcast_pv_forecast_forecast_today") }} kWh


          #Solar #SolarGeneration #Solcast #SolarPV
    action: mastodon.post
mode: single