Connecting SendGrid

SendGrid sends the mail; this product decides what is sent and to whom.

The key

Create one at https://app.sendgrid.com/settings/api_keys. Give it Mail Send, and add the domain authentication and webhook scopes if you want the setup steps below done for you rather than by hand.

A key is not scoped to a domain. Whatever it can do, it can do to the whole account it was issued in -- which is the argument for a subuser.

Subusers, and when you want one

A subuser is a compartment inside your SendGrid account: its own authenticated domains, its own webhook, its own reputation. On this product a subuser is chosen per sender identity and connector pairing, not per account, so one relay can serve a compartmentalised domain and a shared one at the same time.

The reason to use one is blast radius. The reason not to is that subusers need a paid plan and add a step to every change.

Authenticate the domain, not the address

Single-sender verification asks somebody to click a link in a mailbox, which nothing can automate and which breaks the moment that person leaves. Domain authentication is DNS, and DNS is something this product can publish for you if you have connected a DNS provider.

Authenticating the domain also removes the emailed link from the setup entirely.

The event webhook

Bounces, complaints and unsubscribes come back over a webhook, and that feedback is what keeps the suppression list honest. Point SendGrid at the address shown on the connector and turn on signature verification -- without it, anything that finds the URL can tell us an address bounced.

Why click tracking is off

SendGrid rewrites links, and so does this product. A link rewritten twice lands on SendGrid's domain rather than yours, and the click is counted by whichever got there first. Messages go out with SendGrid's tracking disabled in-band, so the branded link and the count are both ours.

Full API documentation: https://www.twilio.com/docs/sendgrid/api-reference