Enabling automatic translation in your Mastodon v4 instance

1. Sign up on DeepL. They have a free plan, though they will collect your credit card information to prevent abuse (which is totally understandable).

2. Visit your DeepL account page and copy your Authentication Key from the section at the bottom of the page. It’ll be a long series of characters.

3. On your Mastodon server, open up your .env.production file and add these lines:

   DEEPL_API_KEY=[the key that you copied above]
   DEEPL_PLAN=free

4. Save the file, and then restart Mastodon:

   $ systemctl restart mastodon-*

You’re all set! Toots in other languages will now display a “Translate” link.