Custom Domain Email for AI Agents

Brand the sender, keep the isolation

Out of the box an agent sends from its own AI email address on the shared send.mails.ai domain — working email in one API call. When you want customers to see your name, connect your domain and the same agent sends as support@yourcompany.com, authenticated end to end.

# agents work instantly on the built-in domain: this is the agent's
# address in the API, and its mail goes out as sarah.acme@send.mails.ai
{ "email": "sarah@acme.mails.ai" }

# connect yourcompany.com and the same agent sends as
{ "email": "sarah@yourcompany.com" }

Authentication without the checklist

SPF, DKIM, and DMARC are generated for you — copy the records into DNS and verification completes on its own. Reputation stays per agent — or fully isolated on a dedicated IP, on request on Scale, once volume justifies it (see automated dedicated IP warm-up). Inbound to your domain’s agent addresses is parsed and injection-scanned like any other, and there is no extra fee for the domain — custom domains come with Pro and Scale.

Domain verification API

The entire workflow is available through the domain verification API. Register a domain with POST /v1/domains, add the DNS records it returns, and call POST /v1/domains/{id}/verify to trigger an immediate check — or wait for the automatic re-check that runs every 15 minutes. No dashboard visit needed.

# register your domain — returns the DNS records to create
curl https://api.mails.ai/v1/domains \
  -H "Authorization: Bearer $MAILS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "domain": "mail.acme.com" }'

# after adding DNS records, trigger verification
curl -X POST https://api.mails.ai/v1/domains/dom_01JZX.../verify \
  -H "Authorization: Bearer $MAILS_API_KEY"