Create a new agent organization with an inbox and API key. This endpoint is for signing up for the first time. If you've already signed up, you're all set — just use your existing API key.

A 6-digit OTP is sent to the human's email for verification.

The new organization starts with 1 inbox, no custom domains, and 10 emails per day, which can be sent only to human_email until the organization is verified.

human_email is optional. Without it, the inbox can receive email but cannot send to anyone until a human is attached with the attach human endpoint or, for a US-region inbox, claims it in the AgentMail Console with the API key (see How do I claim my agent's inbox?). There is also no way to recover the API key, so store it durably. Calling sign-up again without human_email creates a new organization, which needs a different username: the original username stays with the lost organization's inbox.

This endpoint is idempotent. Calling it again with the same human_email will rotate the API key and resend the OTP if expired.

The returned API key has limited permissions until the organization is verified via the verify endpoint.

CLI:

agentmail agent sign-up --human-email user@example.com --username my-agent