Knowledge base
Send email through your own Resend account
Connect your own Resend account: adding a domain, the three DNS records and why the SPF one goes on a subdomain, a sending-access key, and the limits a new account has.
You will need a Resend account and access to your domain's DNS. This is the quickest of the six to set up.
Resend's own documentation: Verify your domain · API keys · Sign up
⚠️ Your own Resend account, not ours. We use Resend for the platform's own mail, and that is a separate account with a separate bill. Attaching yours means your messages leave on your key, your quota and your reputation — which is the whole point.
1. Add your domain
Domains → Add Domain, enter a subdomain such as mail.yourdomain.com, and pick the region closest to your clients.
Resend gives you three records:
| Type | Host | Purpose | | --- | --- | --- | | TXT | resend._domainkey.mail.yourdomain.com | DKIM public key | | MX | send.mail.yourdomain.com | Return-path (bounce handling) | | TXT | send.mail.yourdomain.com | SPF for the return-path domain |
Add all three and press Verify DNS Records.
⭐ Note that the SPF record goes on the send. subdomain, not on your sending domain itself. That is correct and it is why you do not need to touch any SPF record you already have. Resend's return-path is its own subdomain, and SPF is checked against the envelope sender, not against the address your client sees.
2. Create an API key
API Keys → Create API Key. Give it Sending access and, if offered, restrict it to the domain you just added.
⛔ Do not create a Full access key. Sending access is all we need; a full-access key can also read your domains, your logs and your other keys.
⚠️ The key is shown once and starts with re_. Copy it now.
3. Connect it in Zinn®
Open Email sending in your dashboard:
- Provider — Resend (your own account)
- Send from this domain —
mail.yourdomain.com - Resend API key — the key from step 2
4. Send the test and enter the code
Press Send test message to an inbox on a different domain, read the code out of it, and enter it.
When it does not work
"The domain is not verified" — Resend's verification has not gone green yet, or the domain in Send from this domain is not the one you added. Resend matches the exact domain, so adding yourdomain.com does not authorise mail.yourdomain.com.
401 Unauthorized — the key was regenerated, or you copied it with a trailing space. Create a fresh one rather than retyping.
Only your own address receives anything — a Resend account that has not verified any domain can only send to the address it was registered with. Finish step 1.
429 Too Many Requests — Resend rate-limits per API key. If you are sending a large batch of notifications at once this is normal and the messages are retried; if it persists, your plan's limit is the thing to raise.
Still stuck?
Support is included on every plan and answers in your own language.
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