In Zulip, create a homeassistant stream which will contain the received notifications. You also need a bot which you can create in the {{ settings_html|safe }}.

In Home Assistant, you need to add the notify service to your configuration.yaml file. This should look something like this:

The api-key parameter should correspond to your bot's key. The stream parameter is not necessarily required; if not given, it will default to the homeassistant stream. And the URL under `resource` should start with {{ external_api_uri_subdomain }}/v1/external/homeassistant.

Finally, you need to configure a trigger for the service by adding an automation entry in the HomeAssistant configuration.yaml file.

The data object takes at least a message property and an optional title parameter which will be the conversation topic and which defaults to homeassistant if not given.

You'll now get notifications like this:

You just got the Home Assistant integration working. Congratulations!