Inbound MCP server

Connect any MCP client (Claude, Cursor, OpenCode, ChatGPT, agents) to Inbound: manage domains, endpoints, addresses, emails, Guard rules and mailboxes, which are virtual email accounts that agents can read and send from.

Endpoint: https://inbound.new/mcp (Streamable HTTP, stateless)

Three ways to connect

Credential	What the agent gets
OAuth (just add the URL; the client opens Inbound to sign in)	Everything: 50 tools covering the Inbound API, including creating mailboxes and acting as any of them
Account API key (from inbound.new/settings)	The same as OAuth, for scripts and clients without OAuth
Mailbox password (mail_…, returned by create_mailbox)	Only that mailbox: whoami, list_messages, read_message, update_message, get_thread, send_email, reply, download_attachment

The mailbox password is enforced by the Inbound API, not by this server. An agent holding it can only see mail within the mailbox's scopes and can only send as its identity. The same password also works for IMAP (imap.inboundemail.com:993) and SMTP (smtp.inboundemail.com:465).

{
  "mcpServers": {
    "inbound": {
      "type": "http",
      "url": "https://inbound.new/mcp",
      "headers": { "Authorization": "Bearer <api key or mailbox password>" }
    }
  }
}

Leave out headers to use OAuth. Discovery follows the MCP authorization spec: the 401 points to https://inbound.new/.well-known/oauth-protected-resource/mcp, the authorization server is https://inbound.new/api/auth (dynamic client registration, PKCE), and tokens carry the inbound:account scope for the https://inbound.new/mcp audience. This server verifies them against Inbound's JWKS and forwards them to the API.

x-inbound-api-key: <key> is also accepted. Clients that only speak STDIO can use npx mcp-remote https://inbound.new/mcp --header "Authorization:Bearer ${INBOUND_API_KEY}".

Limit the tool list

Add ?toolsets= (or an x-inbound-toolsets header) with any of domains,endpoints,addresses,emails,mailboxes,guard, e.g. https://inbound.new/mcp?toolsets=mailboxes,emails.

Give an agent its own inbox

1. With the account key: create_mailbox { "address": "agent@yourdomain.com", "sending_name": "Support Agent" }.
2. Give the returned password to the agent as its bearer token.
3. The agent loops: list_messages { unread_only: true } → read_message → reply → update_message { is_archived: true }.

Mailboxes, read state and sent mail are stored by Inbound, so they show up in the dashboard and over IMAP too.

Tools (account key)

• Domains: list_domains, get_domain, create_domain, update_domain, delete_domain, enable_domain_dkim
• Endpoints: list_endpoints, get_endpoint, create_endpoint, update_endpoint, delete_endpoint, test_endpoint
• Addresses: list_email_addresses, get_email_address, create_email_address, update_email_address, delete_email_address
• Emails: list_emails, get_email, send_email, reply_to_email, update_email, cancel_scheduled_email, pause_scheduled_email, resume_scheduled_email, retry_email_delivery, list_threads, get_thread, list_attachments, download_attachment
• Mailboxes: list_mailboxes, create_mailbox, update_mailbox, delete_mailbox, rotate_mailbox_password, get_mailbox, list_mailbox_messages, read_mailbox_message, update_mailbox_message, get_mailbox_thread, send_from_mailbox, reply_from_mailbox, download_mailbox_attachment
• Guard: list_guard_rules, get_guard_rule, create_guard_rule, update_guard_rule, delete_guard_rule, check_guard_rule, generate_guard_rule

Development

bun install
bun run dev        # http://localhost:5454/mcp, against production unless INBOUND_API_URL is set
bun run typecheck
INBOUND_API_KEY=... bun run stdio   # STDIO transport

Deployed on Vercel (team inbound, project inbound-mcp) as one function, api/mcp.ts. inbound.new/mcp rewrites to it from the main app.