We have a business app used by our customers. We are building a feature to capture user feedbacks inside the app and email it to our inbox integrated with a ticketing portal. In other words, the users will be using the form in the app and submit their feedback and it has to reach us as they are emailing it.

We have the mail sender script which will use the SMTP host to email the collected feedback.

The problem comes in the part of sending the email as like the user is sending it. We are aware that due to the ANTI-SPAM setup, the generally available email servers (our own) needs the sending domain verification and the from address to match to send the emails. Since the users are using their own domains which we cannot add and verify, we couldn’t make it work in this method.

I see some emails that I receive are sent with the ‘on-behalf of …’ or ‘via ‘ which uses a different from addresses. (Screenshot attached)

(https://i.sstatic.net/AYVagF8J.png)

Is there a way to configure the M365 / Outlook or Google Workspace / Gmail account to send the email this way with any from address. It is fine to see the ‘on-behalf of ..’ or ‘via ‘ in the header.

Are there providers like sendgrid, zeptomail, etc., support this?

I tried a trial account with sendgrid but couldn’t find a way to do this.

I am also aware that this will likely end in the spam folder, and it is a separate mailbox and we can manage the spam manually.

Thanks much for helping out.