Sendmux Email MCP

Sendmux is an email inbox API and email API for AI agents.

- Mailbox operations— Ask your assistant to search, read, organize, and send emails from granted mailboxes, starting withmailbox_list_granted_mailboxeswhen multiple mailboxes are granted.
- Management tools— Direct your assistant to manage team resources like domains, mailboxes, sending accounts, logs, metrics, billing, and webhooks through the Management surface.
- Email sending— Have your assistant send single or batch emails via the Sending surface, which acceptssmx_mbx_keys or owner-approved Sending-resource tokens.
- Documentation search— Use thesearch_sendmuxtool to have your assistant search Sendmux guides and API references for answers.

Connect AI tools to Sendmux documentation and product tools.

Sendmux has two MCP connections. Use Doc Search MCP when you want an AI tool to search Sendmux docs. Use MCP when you want an agent to work with Sendmux tools you authorise.

MCP exposes a curated agent toolset, not every API endpoint. Use the SDKs, CLI, or API reference when you need full endpoint coverage.

MCP exposes the product surfaces you grant.

Hosted MCP is the default when your client supports remote MCP with browser OAuth. It keeps Sendmux in the authorisation flow, avoids distributing manual API keys to agents, and shows only the tools allowed by the grant.

Use the Postman collection when you want to test MCP requests from Postman:

When you connect, Sendmux asks you to choose a team, product surfaces, and mailbox access where relevant. Access tokens are short-lived. Refresh tokens rotate on use and can last up to 30 days unless the connection is disconnected or expires.

If you grant more than one mailbox, start mailbox workflows withmailbox_list_granted_mailboxesand pass the returnedmailbox_idto tools that act on one mailbox.

SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-mailbox SENDMUX_API_KEY=smx_root_... sendmux-mcp-management SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-sending

SENDMUX_MCP_SURFACES=mailbox,management,sending \ SENDMUX_MAILBOX_API_KEY=smx_mbx_... \ SENDMUX_MANAGEMENT_API_KEY=smx_root_... \ SENDMUX_SENDING_API_KEY=smx_mbx_... \ sendmux-mcp

The server validates key prefixes before starting. Management requiressmx_root_. Sending accepts a send-capablesmx_mbx_key or owner-approved Sending-resourcesmx_agent_token. Mailbox accepts ansmx_mbx_key or a scopedsmx_agent_token.

HTTP mode is useful when your MCP client connects to a server URL but you still want to run the package yourself.

SENDMUX_API_KEY=smx_mbx_... \ SENDMUX_MCP_HTTP_BEARER_TOKEN=local-mcp-token \ sendmux-mcp-mailbox --transport http --host 127.0.0.1 --port 8765

The endpoint defaults to/mcp./healthreturns the selected surfaces. HTTP mode requiresSENDMUX_MCP_HTTP_BEARER_TOKENunless you explicitly start it with--allow-unauthenticated-http.

Hosted connections show only the tools allowed by the selected product surfaces, permissions, and mailbox grant. Local servers show the tools for the surfaces and keys you provide at startup.

Enables seamless integration with communication platform that allows you to reach your customers globally across any channel.

Send emails directly from your editor using the Resend API.

Self-hosted email and SMS platform for AI agents — each agent gets a real email address, phone number, inbox, and API key.

Give your AI agent its own email address — instant bot inboxes via API, no human setup required.

Sends emails using the Resend API. Requires a Resend API key.

Context Intelligence API that returns structured, cited answers from email threads, attachments, and Google Drive docs in one API call.

An MCP server for sending emails via the Postmark service, configured through environment variables.

Transactional SendGrid MCP: preflight send, templates, delivery diagnostics, account/console settings, optional Event Webhook receiver. Self-hosted binary, BYOK.