@send16/mcp

Model Context Protocol (MCP) server for the Send16 email platform. This lets AI tools like Claude Desktop, Cursor, Windsurf, and others interact with Send16 directly — sending emails, managing contacts, checking deliverability, and more.

Installation

npm install -g @send16/mcp

Or run directly with npx:

npx @send16/mcp

Prerequisites

You need a Send16 API key. Generate one from your Send16 dashboard under Settings > API Keys.

API keys use the format sk_live_xxxxx.

Configuration

Claude Desktop

Add to your claude_desktop_config.json:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "send16": {
      "command": "send16-mcp",
      "env": {
        "SEND16_API_KEY": "sk_live_xxxxx"
      }
    }
  }
}

If you installed with npx or want to point to a local build:

{
  "mcpServers": {
    "send16": {
      "command": "npx",
      "args": ["@send16/mcp"],
      "env": {
        "SEND16_API_KEY": "sk_live_xxxxx"
      }
    }
  }
}

Cursor

Add to your Cursor MCP settings (.cursor/mcp.json in your project or global config):

{
  "mcpServers": {
    "send16": {
      "command": "send16-mcp",
      "env": {
        "SEND16_API_KEY": "sk_live_xxxxx"
      }
    }
  }
}

Windsurf / Other MCP Clients

Any MCP-compatible client that supports stdio transport can use this server. Point it to the send16-mcp binary with the SEND16_API_KEY environment variable set.

Environment Variables

| Variable | Required | Description | |---|---|---| | SEND16_API_KEY | Yes | Your Send16 API key (sk_live_xxxxx) | | SEND16_API_URL | No | API base URL (default: https://api.send16.com) |

Available Tools

Email Tools

send_email

Send a transactional email.

Parameters:
  to          - Recipient email(s) (string or array, max 50)
  subject     - Email subject line
  html        - HTML body (optional if using template)
  text        - Plain text body (optional)
  from_name   - Sender display name (optional)
  from_email  - Sender email address (optional, must be verified domain)
  reply_to    - Reply-to address (optional)
  template    - Transactional template slug (optional)
  variables   - Template merge variables (optional)

Example prompt: "Send a welcome email to [email protected] with subject 'Welcome to Acme' and a short HTML body"

send_campaign_test

Send a test email for an existing campaign.

Parameters:
  campaignId  - Campaign ID
  testEmail   - Email address to receive the test

create_campaign

Create a new draft campaign.

Parameters:
  name        - Internal campaign name
  subject     - Email subject line
  fromName    - Sender display name
  fromEmail   - Sender email (verified domain)
  replyTo     - Reply-to address (optional)
  previewText - Inbox preview text (optional)

design_email_template

Use AI to generate an email HTML template.

Parameters:
  type         - marketing | transactional | newsletter | announcement | welcome | promotional
  style        - minimal | modern | bold | elegant | playful | corporate
  description  - What the email should contain and its purpose
  brandColor   - Hex color code (optional)
  companyName  - Brand name (optional)

Example prompt: "Design a modern welcome email template for my SaaS product called 'Launchpad' with brand color #4F46E5"

list_campaigns

List campaigns with optional filtering.

Parameters:
  status    - draft | scheduled | sending | sent | paused (optional)
  page      - Page number (default: 1)
  pageSize  - Results per page (default: 20, max: 100)

Contact Tools

create_contact

Add a new contact to your audience.

Parameters:
  email        - Contact email address
  firstName    - First name (optional)
  lastName     - Last name (optional)
  tags         - Array of tag names (optional)
  customFields - Key-value custom fields (optional)

search_contacts

Search contacts by email or name.

Parameters:
  query     - Search string
  page      - Page number (default: 1)
  pageSize  - Results per page (default: 20, max: 100)

list_contacts

List all contacts with optional filters.

Parameters:
  page       - Page number (default: 1)
  pageSize   - Results per page (default: 20, max: 100)
  subscribed - Filter: "true" or "false" (optional)
  tagId      - Filter by tag ID (optional)

import_contacts

Bulk import contacts from CSV data.

Parameters:
  csvData        - CSV string with headers (required column: "email")
  tags           - Tags to apply to all imports (optional)
  updateExisting - Update existing contacts (default: false)

Example prompt: "Import these contacts: email,firstName,lastName\[email protected],John,Doe\[email protected],Jane,Smith"

Domain Tools

list_domains

List all configured sending domains with verification status.

Parameters: (none required)

check_domain_health

Verify DNS records (DKIM, SPF, DMARC) for a domain.

Parameters:
  domainId - Domain ID to check

Analytics Tools

get_campaign_stats

Get performance stats for a specific campaign.

Parameters:
  campaignId - Campaign ID

Returns: send count, delivery rate, open rate, click rate, bounce rate, complaints, unsubscribes.

get_deliverability_status

Get IP warming progress and sending capacity.

Parameters: (none required)

Returns: per-IP warming progress, daily capacity, reputation scores, and aggregate summary.

Development

# Install dependencies
npm install

# Run in development mode
SEND16_API_KEY=sk_live_xxxxx npm run dev

# Build for production
npm run build

How It Works

This server uses the Model Context Protocol stdio transport. When an MCP client (like Claude Desktop) starts the server, it communicates over stdin/stdout using JSON-RPC messages. The server translates MCP tool calls into Send16 API requests and returns structured results.

All tools accept an optional apiKey parameter that overrides the SEND16_API_KEY environment variable, letting you switch between workspaces in a single session.

License

MIT