First, create the stream you'd like to use for Transifex notifications, and subscribe all interested parties to this stream. We recommend the name transifex.

Next, set up a bot for the integration. You'll need the bot's API key to construct a URL for Transifex.

{{ external_api_uri_subdomain }}/v1/external/transifex?api_key=abcdefgh&stream=transifex

where api_key is the API key of your Zulip bot, and stream is the stream name you want the notifications sent to.

Next, in Transifex, go to your project settings page: Project Details → Manage → Edit Project and scroll down to WEB HOOK URL. Paste the URL you constructed into the box and save your changes.

Congratulations! You're done!
Example message: