For prototypes and internal tools, an @agentmailr.com address is fine. For production deployments — customer-facing workflows, enterprise integrations, or any context where the agent represents your brand — your agents should have addresses under your own domain. support-agent@yourcompany.com conveys a very different signal than a7f3k@agentmailr.com.

How It Works

Setting up a custom domain for agent inboxes is a three-step process. You add your domain in the AgentMailr dashboard, configure the required DNS records, and then pass a domain parameter when creating inboxes.

const inbox = await agentmailr.inboxes.create({
  username: "support-agent",
  domain: "yourcompany.com",
});
// inbox.address = "support-agent@yourcompany.com"

// All inbound email to support-agent@yourcompany.com
// is received and processed by AgentMailr.
// OTP extraction, magic link detection, long-poll wait —
// all work identically on custom domains.

const { otp } = await agentmailr.messages.waitForOTP({
  inboxId: inbox.id,
  timeout: 30_000,
});

DNS Records Required

The following DNS records are required to route inbound email to AgentMailr and ensure outbound email is trusted by receiving servers:

  • MX record: routes inbound email to AgentMailr's mail servers. Priority 10.
  • SPF TXT record: authorizes AgentMailr to send email on behalf of your domain. Prevents spoofing.
  • DKIM CNAME: enables cryptographic signing of outbound email. Required for deliverability.
  • DMARC TXT record: tells receiving servers what to do with email that fails SPF or DKIM. Protects your domain reputation.

The AgentMailr dashboard shows the exact record values to add for your domain. DNS propagation typically takes 15-30 minutes. Once propagated, click "Verify DNS" and the domain becomes active for inbox creation.

Use Cases for Custom Domains

  • Enterprise deployments: agents communicating with customers should use company-branded addresses
  • Customer-facing workflows: onboarding agents, support bots, and notification senders all benefit from brand-consistent email identity
  • Multi-tenant products: each customer's agents can use subdomains (agent@customer.yoursaas.com) for complete isolation
  • Deliverability: email from your own domain with proper SPF/DKIM/DMARC is significantly less likely to be marked as spam
  • Reputation management: agent email activity is isolated from your main domain, protecting your domain's sender reputation

Start Free

Custom domains are available on all AgentMailr plans. Add your first domain in the dashboard. No credit card required to start.