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Sendmux has two MCP connections:
  • Documentation MCP lets AI tools search Sendmux guides and API references.
  • Product MCP lets an AI agent use the Sendmux product lines you choose: Management, Mailbox, Sending, or any combination of them.

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Documentation MCP

Use this when you want an AI tool to answer questions from the Sendmux docs.
SettingValue
Server URLhttps://sendmux.ai/docs/mcp
Toolsearch_sendmux

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Connect Claude

1

Open settings

Open Settings and choose Connectors.
2

Add connector

Select Add Connector.
3

Enter the URL

Use https://sendmux.ai/docs/mcp as the server URL.

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Connect Claude Code

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

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Connect Cursor

Add this server to your MCP configuration: 
{
  "mcpServers": {
    "sendmux-docs": {
      "url": "https://sendmux.ai/docs/mcp"
    }
  }
}

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Connect VS Code

Add this server to your settings: 
{
  "mcp": {
    "servers": {
      "sendmux-docs": {
        "type": "http",
        "url": "https://sendmux.ai/docs/mcp"
      }
    }
  }
}

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Rate limits

ScopeLimit
Per user IP5,000 requests per hour
Per documentation site10,000 requests per hour

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Product MCP

Use the Product MCP when you want an agent to act inside Sendmux. A single connection can expose exactly the product lines you authorise:
Product lineWhat the agent can doCredential authority
ManagementManage domains, mailboxes, sending accounts, webhooks, logs, metrics, and billing data.Team-level access
MailboxRead, search, organise, thread, and send from selected mailboxes.Selected mailbox access
SendingSend outbound email without mailbox reading tools.Sending access
Choosing more product lines never grants more authority than your team role, selected mailbox set, and consent allow. Tools for product lines you did not authorise are not shown to the agent.

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Hosted connection

Use the hosted Product MCP when your AI tool supports remote MCP with OAuth.
SettingValue
Server URLhttps://mcp.sendmux.ai/mcp
Authorisation serverhttps://app.sendmux.ai
When you connect:
1

Start the connection

Add https://mcp.sendmux.ai/mcp in your AI tool, then sign in to Sendmux when prompted.
2

Choose a team

Pick the team that should own the connection.
3

Choose product lines

Select Management, Mailbox, Sending, or any combination. Choose all three when the agent should see every curated Sendmux tool.
4

Choose mailboxes

If you select Mailbox, choose one or more mailboxes the agent can use. Use search or Select all when your team has many mailboxes.
5

Review and authorise

Review the requested access, then select Authorise. Management permissions are grouped by area with None, Read, Full, and Customise choices, so you can open individual scopes only when you need them.
Connected apps use short-lived access tokens that last 15 minutes. Refresh tokens rotate on use and can last up to 30 days unless the connection is disconnected or the grant expires. The connection does not create a manual smx_root_ or smx_mbx_ API key. When more than one mailbox is granted, agents can call mailbox_list_granted_mailboxes to search the granted set and pass mailbox_id to mailbox tools. If only one mailbox is granted, mailbox tools use it by default. Re-authorising the same hosted connection replaces the previous product-line and mailbox selections for that app. Product lines or mailboxes you remove during re-authorisation disappear from the agent’s tool list or allowed mailbox targets. Hosted Product MCP requests keep the same permission, sending-scope, and rate-limit checks as direct Sendmux API requests before each request is accepted. For example, adding Sending tools to an agent does not let it send from mailboxes, sending accounts, or account groups outside the access you granted.

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Local connection

Use the local command when your AI tool runs MCP servers on your machine. Run one product line: 
SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-mailbox
SENDMUX_API_KEY=smx_root_... sendmux-mcp-management
SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-sending
Run a chosen combination: 
SENDMUX_MCP_SURFACES=mailbox,sending \
SENDMUX_MAILBOX_API_KEY=smx_mbx_... \
sendmux-mcp
Run all three product lines: 
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
You can also pass the same choices as command flags: 
sendmux-mcp \
  --surfaces mailbox,management,sending \
  --mailbox-api-key smx_mbx_... \
  --management-api-key smx_root_... \
  --sending-api-key smx_mbx_...
Management requires an smx_root_ key. Mailbox and Sending require an smx_mbx_ key. A key with lower authority will not expose higher-authority tools. Use separate keys for separate local product lines when that is how your team grants least-privilege access. For example, a local all-three setup can use one management key plus separate mailbox and sending keys. Local MCP with a manual mailbox key acts as that one mailbox. Hosted Product MCP can grant a mailbox set and target each mailbox by mailbox_id.

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Tool coverage

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