Custom inbox domain

By default MailAgent creates addresses on your Resend receiving domain (INBOX_DOMAIN, e.g. abc123.resend.app). To use your own subdomain (e.g. inbox.yourcompany.com), configure Resend receiving + DNS.

1. Resend receiving domain

1. Resend Dashboard → Domains → add domain or use existing.
2. Enable Receiving and add MX records Resend shows.
3. Copy the receiving hostname (e.g. your-id.resend.app).

2. MailAgent Worker

npx wrangler secret put INBOX_DOMAIN
# paste: your-id.resend.app

3. Webhook

Point Resend inbound webhook to:

https://api.webmailagent.com/webhooks/resend

4. Verify

curl -s -X POST "$MAILAGENT_API_URL/v1/inboxes" \
  -H "Authorization: Bearer $MAILAGENT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"ttlMinutes":5}' | jq .address

Send a test email to that address from an allowed sender.

Branded subdomain (advanced)

Resend may offer custom receiving on your apex/subdomain per their docs. MailAgent does not proxy SMTP — all mail flows through Resend inbound → webhook.

Questions: hello@webmailagent.com