This shows how to use OAuth with Zoho to send an E-Mail from a custom domain. It uses Flask for catching the OAuth tokens (redirect url) and to show how to send an E-Mail from a server using a custom domain. It also includes a thread that periodically updates the access token using the refresh token, since it becomes invalid after one hour.

How to set up

1. Setup in the Zoho API Console as redirect uri: http://127.0.0.1:5000/callback/
2. Copy the client id and secret into send_mail.py at the top.
3. Configure which email to send to etc. at the top of send_mail.py.

Be very careful with the API domain - currently I use .eu everywhere. If you need to use .com, change both API urls!

How to use

Click the URL printed on console. This only has to be done once when setting up the server. Afterwards you can go to the sendmail endpoint (127.0.0.1:5000/sendmail/) to automatically send an E-Mail using your custom domain.