# Email Inbox API + Sending by Sendmux A Sendmux MCP server that hands your agent an inbox and an outbox: inbound mail, attachments, search, live events and webhooks. - MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed · ★ 62 - Author: Sendmux - License: MIT · policy=link-only · description only; the file stays with the author - Source: https://github.com/Sendmux/sendmux-sdk/tree/HEAD/packages/python/mcp - Updated: 2026-10-24 - HTML: https://affpapa.org/en/nevibecode/mcp/email-inbox-api-sending-by-sendmux ## What it does Three tool surfaces ship in one package. Mailbox covers the inbox, sending covers outbound mail, management covers domains and resources. Inbound messages arrive parsed into clean JSON, and attachments, search, live events and webhooks sit alongside them. Provider routing is handled on the Sendmux side. Locally you install with `pip install sendmux-mcp` and pick a surface through `sendmux-mcp-mailbox`, `sendmux-mcp-management` or `sendmux-mcp-sending`. The generic `sendmux-mcp` command takes `SENDMUX_MCP_SURFACES` and can run several surfaces at once. `stdio` is the default transport. HTTP mode listens on `127.0.0.1:8765/mcp` and wants its own bearer token unless you opt out. Python 3.10 or newer is required. Sending tools need a send-capable `smx_mbx_*` key or an owner-approved `smx_agent_*` token scoped to the Sending resource; mailbox tools need a mailbox-scoped key, management tools a root `smx_root_*` key. Version 2.0.0 dropped local `file_path` and roots inputs from the attachment tools, so keep your working package environment and client config before upgrading a self-managed install — a package rollback will not undo uploads or sends that already went out. There is a public hosted endpoint at `https://mcp.sendmux.ai/mcp`. Use HTTP transport with OAuth there and skip manual `Authorization` headers or API keys. The same runtime serves A2A 1.0 at `https://a2a.sendmux.ai/a2a/v1`. ## Requirements - Needs: Node.js (commands run via npx) - Remote server: `https://mcp.sendmux.ai/mcp` - Environment variables: `SENDMUX_MCP_SURFACES`, `SENDMUX_MAILBOX_API_KEY`, `SENDMUX_MANAGEMENT_API_KEY`, `SENDMUX_SENDING_API_KEY` — keys and tokens: ask the human for the values, never commit them or put them in shared files. ## Install ### Claude Code (native platform) 1. **Platform CLI: remote server** ```bash claude mcp add --transport http sendmux-mcp https://mcp.sendmux.ai/mcp ``` 2. **Platform CLI** ```bash claude mcp add --env SENDMUX_MCP_SURFACES= --env SENDMUX_MAILBOX_API_KEY= --env SENDMUX_MANAGEMENT_API_KEY= --env SENDMUX_SENDING_API_KEY= --transport stdio mcp -- npx -y sendmux-mcp ``` Replace <…> with your own values ### Codex 1. **Platform CLI: remote server** ```bash codex mcp add mcp --url https://mcp.sendmux.ai/mcp ``` 2. **Platform CLI** ```bash codex mcp add mcp --env SENDMUX_MCP_SURFACES= --env SENDMUX_MAILBOX_API_KEY= --env SENDMUX_MANAGEMENT_API_KEY= --env SENDMUX_SENDING_API_KEY= -- npx -y sendmux-mcp ``` Replace <…> with your own values ### Cursor **Config file** File `.cursor/mcp.json`: ```json { "mcpServers": { "mcp": { "url": "https://mcp.sendmux.ai/mcp" } } } ``` File `.cursor/mcp.json`: ```json { "mcpServers": { "mcp": { "command": "npx", "args": [ "-y", "sendmux-mcp" ], "env": { "SENDMUX_MCP_SURFACES": "", "SENDMUX_MAILBOX_API_KEY": "", "SENDMUX_MANAGEMENT_API_KEY": "", "SENDMUX_SENDING_API_KEY": "" } } } } ``` Replace <…> with your own values ### GitHub Copilot **Config file** File `.vscode/mcp.json`: ```json { "servers": { "mcp": { "type": "http", "url": "https://mcp.sendmux.ai/mcp" } } } ``` File `.vscode/mcp.json`: ```json { "servers": { "mcp": { "type": "stdio", "command": "npx", "args": [ "-y", "sendmux-mcp" ], "env": { "SENDMUX_MCP_SURFACES": "", "SENDMUX_MAILBOX_API_KEY": "", "SENDMUX_MANAGEMENT_API_KEY": "", "SENDMUX_SENDING_API_KEY": "" } } } } ``` Replace <…> with your own values ### Gemini CLI 1. **Platform CLI: remote server** ```bash gemini mcp add -t http mcp https://mcp.sendmux.ai/mcp ``` 2. **Platform CLI** ```bash gemini mcp add -e SENDMUX_MCP_SURFACES= -e SENDMUX_MAILBOX_API_KEY= -e SENDMUX_MANAGEMENT_API_KEY= -e SENDMUX_SENDING_API_KEY= mcp npx -y sendmux-mcp ``` Replace <…> with your own values ## When to use it - read incoming mail from a mailbox as JSON - send a message with an attachment from an agent - search a mailbox through a tool call - subscribe to new mail with a webhook - split mail work across mailbox, sending and management surfaces ## Example prompts - List the latest inbox messages and return them as JSON - Send an email with the attachment listed in `recipients.txt` - Set up a webhook for new mail in my mailbox ## Similar - [REA](https://affpapa.org/en/nevibecode/mcp/rea.md) — MCP server · ★ 386989 - [GitHub](https://affpapa.org/en/nevibecode/mcp/github.md) — MCP server · ★ 33918 - [Netdata](https://affpapa.org/en/nevibecode/mcp/netdata.md) — MCP server · ★ 81115 - [browser-use](https://affpapa.org/en/nevibecode/mcp/browser-use.md) — MCP server · ★ 119160 - [Codebase Memory](https://affpapa.org/en/nevibecode/mcp/codebase-memory.md) — MCP server · ★ 47392 - [mcp-server](https://affpapa.org/en/nevibecode/mcp/mcp-server.md) — MCP server · ★ 43872 --- NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md