SOP: Set Up a Custom Domain

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Sending from your own domain gives you control over sending reputation, the single most important deliverability factor. Setup is three steps: add the domain, set DNS records, verify.

1. Add the domain

AgentMail registers the domain and immediately returns the DNS records you need.

from agentmail import AgentMail
client = AgentMail()

domain = client.domains.create("your-domain.com")
print("DNS Records:", domain.records)

curl -X POST https://api.agentmail.to/v0/domains \
  -H "Authorization: Bearer $AGENTMAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "domain": "your-domain.com" }'

You can also add a domain from the Console: Domains → Add Domain → enter the name → Create.

2. Add the DNS records

Copy the returned records (SPF, DKIM, DMARC, and MX) into your DNS provider. Registrar-specific walkthroughs:

• Cloudflare
• GoDaddy
• Namecheap
• Route 53

MX record conflicts

A domain already receiving mail (e.g. Google Workspace) has existing MX records. Adding AgentMail's MX can conflict. See MX record conflicts.

3. Verify

DNS propagation can take minutes to hours. Trigger verification once records are live:

curl -X POST https://api.agentmail.to/v0/domains/your-domain.com/verify \
  -H "Authorization: Bearer $AGENTMAIL_API_KEY"

If it stays unverified, see Domain not verifying.

4. Warm the domain

New domains have no reputation. Ramp volume gradually. See Domain warming. For high-volume sending, register multiple domains and spread volume across them.

Related

Custom Domains concept · Domains API · SPF/DKIM/DMARC · Email deliverability