Reckon MCP Server

Verify email addresses in real-time directly from Claude, ChatGPT, Cursor, Windsurf, or any MCP-compatible AI client. Powered by Reckon.

Example

You: Verify sales@acme.com

Assistant: I verified sales@acme.com using the Reckon email verification tool. Here are the results:

• Status: Valid
• Format: Valid email format
• Domain: acme.com exists and accepts mail
• Risk flags: Role-based address (sales@), not disposable, not accept-all

One credit was used for this verification. You have 4,999 credits remaining.

Requirements

• A Reckon account, which comes with cost-free sandbox email addresses as well as 25 credits for real-world trialing.
• An active Reckon subscription (see pricing)
• A credit balance higher than zero

Quick setup

Endpoint: https://mcp.reckonapp.io/mcp

Our Claude and ChatGPT connectors are currently under review — once approved, those will be the easiest way to connect. In the meantime (and for all other MCP clients), add the endpoint in your client's MCP settings and sign in with your Reckon account when prompted.

For clients that don't support OAuth (like Cursor), use an API key instead. Add to .cursor/mcp.json:

{
  "mcpServers": {
    "reckon": {
      "url": "https://mcp.reckonapp.io/mcp",
      "headers": {
        "X-API-Key": "YOUR_API_KEY"
      }
    }
  }
}

Get your API key at app.reckonapp.io/api-keys.

Tools

verify_email

Verify an email address. Returns deliverability status, format validity, domain info, and risk flags (disposable, role-based, accept-all, mailbox full, plus addressing). Each call consumes one credit.

Input:

Example response:

{
  "email_address": "user@example.com",
  "status": "valid",
  "status_meta": {
    "valid_format": true,
    "domain_exists": true,
    "accept_all": false,
    "disposable": false,
    "role_based": false,
    "mailbox_full": false,
    "plus_address": false
  },
  "domain_meta": {
    "domain": "example.com",
    "mailbox_provider": "example.com"
  }
}

check_credits

Check the remaining email verification credit balance for your account. No input required.

Example response:

{
  "balance": 5000,
  "asOf": "2026-03-22T14:00:00Z"
}

Authentication

Most clients authenticate via OAuth — you sign in with your Reckon account when prompted and a dedicated API key is created automatically.

For clients that don't support OAuth (like Cursor), pass your API key via the X-API-Key header. Get a key at app.reckonapp.io/api-keys.

You can manage, pause, or revoke keys anytime from your API Keys dashboard.

Discovery

Registries and clients can read machine-readable MCP metadata at https://mcp.reckonapp.io/.well-known/mcp/server-card.json (server info, OAuth, tools, and the same optional API key config schema used for Smithery).

Smithery: If the dashboard warns that no config schema was provided, attach the JSON Schema from smithery-config-schema.json when publishing or updating the external URL (see Smithery external publish — config schema). Example with the Smithery CLI:

smithery mcp publish "https://mcp.reckonapp.io/mcp" -n "@your-namespace/your-server-name" \
  --config-schema "$(jq -c . smithery-config-schema.json)"

Interactive sign-in (OAuth) remains the primary path; the schema only adds an optional API key for environments that need header-based access.

Third-party directories (for example mcp.so): The live MCP URL (/mcp) answers with 401 and OAuth metadata when neither a Bearer access token nor X-API-Key is present, so a crawler that only opens a session against /mcp cannot complete initialize / tools/list and may show an empty tool list. Prefer pointing the listing at the server card if the product supports a static metadata URL, use directory-specific OAuth if offered, or supply a crawl API key in the directory’s settings if it forwards X-API-Key on MCP requests.

Links

• Get an API key: app.reckonapp.io/signup
• Manage API keys: app.reckonapp.io/api-keys
• Support: support.reckonapp.io
• Privacy: reckonapp.io/privacy
• Terms of Service: reckonapp.io/privacy
• MCP Protocol: modelcontextprotocol.io

License

MIT