MCP

Your email API,
AI-native.

Control your email infrastructure from any AI assistant. Send emails, debug delivery, and monitor domains through natural language.

Works with your favorite AI tools

Claude

ChatGPT

Cursor

Windsurf

Talk to your email infrastructure

Natural language commands that translate into real API actions.

Send emails

Send a welcome email to john@example.com using the welcome-v2 template with their name and activation link.

Email sent successfully to john@example.com using template welcome-v2. Message ID: msg_a1b2c3d4. Delivery status: accepted.

Debug delivery

Why did the email to sarah@company.com bounce yesterday?

The email to sarah@company.com bounced at 2024-01-15 14:32 UTC with a 550 5.1.1 error: recipient mailbox does not exist. The address has been added to your suppression list.

Check domains

Are all my sending domains properly authenticated?

You have 3 sending domains configured. app.yoursite.com: DKIM verified, SPF verified, DMARC verified. mail.yoursite.com: DKIM verified, SPF verified, DMARC pending. notify.yoursite.com: All records verified.

Monitor API

Show me the API errors from the last 24 hours.

Found 3 API errors in the last 24 hours. 2x 422 validation errors on /v1/send (missing "to" field). 1x 429 rate limit exceeded at 03:14 UTC from IP 192.168.1.50. All other 12,847 requests returned 200.

Available actions

Every action maps to a real Lettr API endpoint. Your AI agent gets the same capabilities as your code.

send_email

Send a raw email with full control over headers, body, and attachments

send_template_email

Send an email using a pre-built template with dynamic variables

browse_email_events

Search and filter email events like deliveries, opens, and bounces

browse_api_logs

View API request and response logs with full payloads

list_sending_domains

List all configured sending domains and their authentication status

list_tracking_domains

View tracking domains used for open and click tracking

list_api_keys

List all API keys with their permissions and last used timestamps

list_webhooks

View configured webhook endpoints and their delivery status

What you can build

Use the MCP server as a building block for AI-powered email workflows.

Send test emails from chat

Ask your AI assistant to send a test email to any address using any template. Perfect for QA workflows.

Debug delivery issues

Paste a recipient email and ask why it bounced. Get bounce codes, timestamps, and suppression status instantly.

Audit domain authentication

Ask your agent to verify all sending domains have proper DKIM, SPF, and DMARC records configured.

Monitor API health

Query recent API logs for errors, rate limits, and response times without leaving your editor.

Generate integration code

Describe what email you want to send and get working code with the correct template IDs and variables.

Automate email ops

Build AI-powered workflows that react to delivery events, clean up suppression lists, and rotate API keys.

Get started in 30 seconds

Add the Lettr MCP server to your AI tool configuration. One endpoint, one API key.

mcp.json

{
  "mcpServers": {
    "lettr": {
      "url": "https://mcp.lettr.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Security by design

The MCP server uses your existing API key with the same permissions and rate limits as direct API calls. All actions are logged and auditable. Scoped API keys let you limit what your AI agent can do -- read-only access for monitoring, or full write access for automation.

Start sending for free →

3,000 emails/month free. No credit card required.

Your email API,AI-native.