Hey there @theo.voglimacci1,
I’m not too familiar with Sendinblue because I use Postmark, but usually when you’re sending on behalf of your users you have 1 of three options in Postmark:
- Add their domain to your account, so it’s verified (Postmark’s recommended)
- Add them as a verified sender
- Send from your domain, but use their name in the “From Name”
These are all usually done via their API
Now… gotta stop my rambling, but looking at Sendinblue, it looks like their API does support this, just follow their documentation here: https://developers.sendinblue.com/reference#createsender
In terms of verifying if they are a verified sender, you can use the GET request with the Sendinblue API to check that: https://developers.sendinblue.com/reference#getsenders-1
I’m not sure if you’d rather give your user both the option to create a verified sender and attach their domain to your account, but if you want to do that I’d look into Sendinblue’s API capabilities.
Hope this helps!