Sending emails with the same address via both SendGrid and Google Workspaces

Question

I'd like to send emails programmatically via SendGrid (from [email protected]), but have replies to that email come to my Google Workspaces inbox for [email protected]). I would then like to reply to the customer from Google Workspaces.

The closest question related to this I could find is Setup | G Suite + Sendgrid for transactional email, but that was a fairly different use-case.

So in my usecase, emails to the customer would come from [email protected] via EITHER SendGrid or Google Workspaces.

Here's a article from MailGun that talks about a similiar pattern

My questions:

1. Will this result in deliverability issues, having emails sometimes come with different signing keys/domains? I don't understand email signing particularly well.
2. Is there anyway to have replies to the email address go to BOTH SendGrid and Google Workspaces, so I'll have it in my inbox but can also get it posted to a webhook by SendGrid? I think the answer is no, but figured I'd ask.
3. Any other considerations I should keep in mind for this strategy? Is this a poor idea for some reason?

Thanks!

Answer 1

1. Yes, this will result in deliverability issues. You should use the same domain for both sending and receiving.

2. No, you can't have replies go to both. You can have replies go to a webhook, but you can't have them go to both a webhook and a mailbox.

3. Final consideration: This is a poor idea. You should use the same domain for both sending and receiving. If you want to use SendGrid, you should use SendGrid for both sending and receiving. If you want to use Google Workspaces, you should use Google Workspaces for both sending and receiving. You can't use both at the same time.

Another consideration: If you're sending a lot of emails, you might get flagged as a spammer if you're sending from multiple domains.

Answer 2

The company I work for does something similar that might be helpful for your scenario.

We have a number of systems that send emails via SendGrid e.g. Auth0, Salesforce, various bespoke systems, etc. Some of these use native integrations to SendGrid, some use SMTP relaying, and others send emails programatically via the SendGrid API.

We've implemented sender auth (i.e. DKIM) in SendGrid for our domain e.g. mydomain.example.com, but we don't handle replies in SendGrid as we want replies to go to a different system - specifically our contact center system (which is the main systems our help desk staff use). Help desk staff would then reply to emails from within the contact center system. Note: we needed to configure DKIM for both SendGrid as well as the contact center system (as both currently send emails from mydomain.example.com), but in the future the intent was to implement a SMTP relay in the contact center system (to SendGrid) so that all sending goes through SendGrid.

I'm a bit fuzzy on the fine-grained implementation details of how we handle replies, but essentially we point the (single) MX record for mydomain.example.com to a third-party email protection system which scans the emails and forwards them to Office 365 mailboxes which subsequently forwards them to our contact centre system. I believe Office 365 is really only there for email posterity. AFAIK you should be able to point the MX record to anything that can handle SMTP.

In your scenario you should be able to configure the MX record for the mydomain.example.com domain to point at your Google Workspaces. This will allow you to send emails from SendGrid and use Google Workspaces to handle the sending and receiving of replies.

Not sure if you can configure SMTP relaying in Google Workspaces (i.e. to relay through SendGrid), but this would mean you'd only need to configure DKIM for SendGrid. All emails would be sent by SendGrid and replies would be go to Google Workspaces.