# Sendmux MCP server

> Send email and manage inboxes, domains and mailboxes through Sendmux, with attachments, search, live events and webhooks.

- Listing: https://mcp.tc/i/sendmux
- Connect: use the server's own URL `https://mcp.sendmux.ai/mcp` (OAuth sign-in at the server); clients connect to it directly. The listing link is a page, not an MCP endpoint.
- Type: remote (Streamable HTTP)
- Auth: OAuth sign-in
- Category: [Communication & Meetings](https://mcp.tc/c/communication)
- Vendor: Sendmux
- Homepage: <https://sendmux.ai/docs/guides/mcp>
- Repository: <https://github.com/Sendmux/sendmux-sdk/tree/HEAD/packages/python/mcp>
- Package: npm `sendmux-mcp`

## About

Connects an assistant to the Sendmux email platform. Based on the OAuth scopes and registry description, it covers sending email, reading and searching inbox messages, managing domains and mailboxes, and viewing logs, analytics and billing information.

It runs as a hosted streamable HTTP endpoint at https://mcp.sendmux.ai/mcp with OAuth sign-in and a Sendmux account. A local npm package (sendmux-mcp, Node.js 22 or later) forwards stdio clients to the hosted server. A separate Python package supports local API-key use.

## What it can do

- Send email, including attachments
- Search and read inbox messages
- Create, verify and read sending domains
- Create and manage mailboxes
- Read email logs and analytics
- View billing information

## Example prompts

- "Send an email to alex@example.com with the attached report"
- "Search my inbox for messages about the invoice from last week"
- "Add a new sending domain and show its verification status"
- "Show email delivery logs for the past 24 hours"

## Install

### Claude Code

1. Run this in a terminal, in your project folder:

```bash
claude mcp add --transport http sendmux https://mcp.sendmux.ai/mcp
```

2. Start Claude Code, type `/mcp`, pick **sendmux** and choose **Authenticate**. A browser window opens for the Sendmux sign-in.

Add `--scope user` to make it available in every project, not just this one.

### Claude Desktop

1. Open **Settings → Connectors** and click **Add custom connector**.

2. Name it **Sendmux** and paste this URL:

```url
https://mcp.sendmux.ai/mcp
```

3. Click **Add**, then **Connect**, and sign in when Sendmux asks.

Claude Desktop’s JSON config file only starts local servers. Remote servers go through Connectors, and connectors you add on claude.ai show up here too.

### claude.ai

1. Open the connector form on claude.ai. This button fills in the name and URL for you:

[Add to claude.ai](<https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Sendmux&connectorUrl=https%3A%2F%2Fmcp.sendmux.ai%2Fmcp>) (opens connector settings)

2. Check that the URL reads `https://mcp.sendmux.ai/mcp` and click **Add**.

3. Click **Connect** and sign in when Sendmux asks.

Free plans allow one custom connector. On Team and Enterprise plans an owner adds it under **Organization settings → Connectors**.

### ChatGPT

1. On chatgpt.com, open **Settings → Security and login** and turn on **Developer mode**.

2. Go to `chatgpt.com/plugins` and click **+** to create an app for a remote MCP server.

3. Paste `https://mcp.sendmux.ai/mcp` as the server URL and choose **OAuth**. ChatGPT sends you to Sendmux to sign in.

Developer mode is available on the web for Plus, Pro, Business, Enterprise and Education accounts.

### Cursor

[Add to Cursor](<https://cursor.com/install-mcp?name=sendmux&config=eyJ1cmwiOiJodHRwczovL21jcC5zZW5kbXV4LmFpL21jcCJ9>) (opens Cursor)

Or add it by hand to `~/.cursor/mcp.json` (all projects) or `.cursor/mcp.json` (this project):

`mcp.json`:

```json
{
  "mcpServers": {
    "sendmux": {
      "url": "https://mcp.sendmux.ai/mcp"
    }
  }
}
```

Cursor shows **Needs login** next to the server. Click it to sign in.

### VS Code

[Install in VS Code](<https://vscode.dev/redirect/mcp/install?name=sendmux&config=%7B%22type%22%3A%22http%22%2C%22url%22%3A%22https%3A%2F%2Fmcp.sendmux.ai%2Fmcp%22%7D>) (opens VS Code)

Or from a terminal:

```bash
code --add-mcp '{"name":"sendmux","type":"http","url":"https://mcp.sendmux.ai/mcp"}'
```

Or commit it to the repo in `.vscode/mcp.json`:

`.vscode/mcp.json`:

```json
{
  "servers": {
    "sendmux": {
      "type": "http",
      "url": "https://mcp.sendmux.ai/mcp"
    }
  }
}
```

VS Code asks you to sign in the first time the server starts.

### Devin Desktop

1. Add it to `~/.config/devin/mcp_config.json` (macOS and Linux) or `%APPDATA%\devin\mcp_config.json` (Windows):

`mcp_config.json`:

```json
{
  "mcpServers": {
    "sendmux": {
      "serverUrl": "https://mcp.sendmux.ai/mcp"
    }
  }
}
```

2. Refresh the MCP server list in Cascade and sign in when asked.

Devin Desktop is the new name for Windsurf. It reads `serverUrl` (or `url`) for remote servers.

### Codex

```bash
codex mcp add sendmux --url https://mcp.sendmux.ai/mcp
codex mcp login sendmux
```

Or edit `~/.codex/config.toml` directly:

`config.toml`:

```toml
[mcp_servers.sendmux]
url = "https://mcp.sendmux.ai/mcp"
```

### Gemini CLI

```bash
gemini mcp add --transport http sendmux https://mcp.sendmux.ai/mcp
```

Then, inside Gemini CLI, run `/mcp auth sendmux` to sign in.

This adds it to the current project. Add `-s user` to use it everywhere.

### Any client

Most clients accept this shape. Some name the URL field differently: `serverUrl` in Devin Desktop, `httpUrl` in Gemini CLI’s settings file.

```json
{
  "mcpServers": {
    "sendmux": {
      "type": "http",
      "url": "https://mcp.sendmux.ai/mcp"
    }
  }
}
```

Zed puts servers under `context_servers` in its settings. Cline needs `"type": "streamableHttp"`, or it assumes SSE.

Client only starts local servers? Bridge it with `npx -y mcp-remote https://mcp.sendmux.ai/mcp`.

## Details

- Server version: 2.2.0
- Last checked: 2026-10-04 (reachable, asks for credentials)
- Listed: 2026-10-04
- Updated: 2026-10-04

---
Source: https://mcp.tc/i/sendmux (mcp.tc is an independent directory, not affiliated with this server's publisher). Corrections: https://mcp.tc/report