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ContactLint

Official registry Productivity

Validate emails (MX, disposable, role, typo) and phone numbers, singly or in batches, for AI agents.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http contactlint 'https://contactlint.com/mcp' --header 'Authorization: <Bearer token: your ContactLint API key (free at https://contactlint.com/signup)>'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "contactlint": {
            "type": "http",
            "url": "https://contactlint.com/mcp",
            "headers": {
                "Authorization": "<Bearer token: your ContactLint API key (free at https://contactlint.com/signup)>"
            }
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. ContactLint MCP server
  2. Tools
  3. Configuration
  4. Billing
  5. Free tools
  6. License

ContactLint MCP server

ContactLint is a hosted MCP server that checks email addresses and phone numbers before your agent saves or uses them. It runs at a public URL, so there is nothing to install.

This repository holds the listing files only (this README, server.json and a client config example). The server itself is hosted by ContactLint.

Tools

ToolInputWhat it does
validate_emailemailChecks syntax, MX and A records over DNS-over-HTTPS, known disposable domains, role addresses (admin@, no-reply@) and free providers, and suggests a fix when the domain looks like a typo of a major provider (gmial.com).
validate_emailsemails (1 to 50 addresses)Same checks as validate_email for up to 50 addresses in one call. Returns one result per address in the same order plus a summary of verdicts.
validate_phonephone, optional country (ISO 3166-1 alpha-2 default region, for example US)Parses and validates a phone number: valid and possible flags, line type, region, E.164, national and international formats.

ContactLint does not connect to mail servers (no SMTP probing), so it cannot confirm that a mailbox exists or detect catch-all domains.

initialize and tools/list work without a key, so clients and directory scanners can read the tool list. tools/call needs an API key.

Configuration

One setting is required:

NameRequiredDescription
apiKeyyesYour ContactLint API key. Get a free key at https://contactlint.com/signup

Send it as an Authorization: Bearer <apiKey> header (an x-api-key header also works).

Example client config (see examples/mcp.json):

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

examples/config-schema.json describes the apiKey setting as JSON Schema, for directories and clients that ask for one.

Billing

  • One check per address or number checked. A validate_emails call with 20 addresses uses 20 checks.
  • Addresses whose DNS lookup fails come back unknown and are not billed.
  • If a key does not have enough checks for a whole validate_emails list, nothing is checked or billed.
  • 100 checks per month are free, no card needed.
  • Credit packs: 5,000 checks for $9, 25,000 for $35, 100,000 for $99.

Free tools

Free browser tools (disposable email checker, phone number validator, disposable domain list) are at https://contactlint.com/tools

License

MIT, see LICENSE.

Frequently asked questions

What is ContactLint?

Validate emails (MX, disposable, role, typo) and phone numbers, singly or in batches, for AI agents.

How do I install ContactLint?

It runs as a remote server. In Claude Code: claude mcp add --transport http contactlint 'https://contactlint.com/mcp' --header 'Authorization: <Bearer token: your ContactLint API key (free at https://contactlint.com/signup)>'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does ContactLint need an API key?

Yes. It expects Authorization, which you set in its configuration.

Is ContactLint open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains ContactLint?

It is published by zksyncer. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.