Use case

Email infrastructure for AI agents

An agent that sends and receives email needs an identity, a way to poll for messages without losing one on a crash, and none of the OAuth consent screens or MIME-parsing plumbing a human-inbox integration requires.

How a mailbox works

Create a mailbox and the agent has a real address on inbound.euromail.dev — no domain to verify, no OAuth grant, no mailbox provider account. From there the lifecycle is four steps, and the third one is the part most inbox integrations get wrong.

  1. Create. One POST /v1/agent-mailboxes call returns an address like [email protected]. Pass a custom local_part for a fixed address such as [email protected] instead of a generated one.
  2. Poll. GET /messages/next long-polls for up to 60 seconds and returns as soon as a message arrives — no webhook endpoint to expose, no queue infrastructure to run.
  3. Lease. A successful poll leases the message for 5 minutes, hiding it from other pollers, and hands back a lease_token. If the agent crashes mid-processing, the lease expires and the message returns to the queue automatically — nothing is silently dropped.
  4. Acknowledge. Ack the lease_token once processing succeeds, or nack it to requeue immediately instead of waiting out the lease.
Tool-calling

Or skip the API entirely

The @euromail/mcp-server package exposes sending, delivery status, domain management, and more as Model Context Protocol tools. Add it to Claude Desktop, Cursor, or any MCP-compatible client with an API key in the environment, and the assistant calls the tools directly — no integration code to write or maintain.

{
  "mcpServers": {
    "euromail": {
      "command": "npx",
      "args": ["@euromail/mcp-server"],
      "env": { "EUROMAIL_API_KEY": "em_live_..." }
    }
  }
}

Related

  • Agent mailboxes

    A persistent address on inbound.euromail.dev with at-least-once delivery.

  • MCP server

    Model Context Protocol tools so an assistant can send and check email without glue code.

  • Inbound email

    Route incoming mail to a webhook or a mailbox by address or pattern.

Start sending free Read the agent mailboxes guide