DomainCheckr MCP Server

Check domain name availability instantly using RDAP. No API key or installation required. Works as a remote MCP server.

Quick Start

This is a remote MCP server -- no local installation needed. Just add the URL to your MCP client.

Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "domaincheckr": {
      "url": "https://domaincheckr.fly.dev/mcp"
    }
  }
}

Config file location:

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

Claude Code

claude mcp add domaincheckr --transport http https://domaincheckr.fly.dev/mcp

Cursor

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "domaincheckr": {
      "url": "https://domaincheckr.fly.dev/mcp"
    }
  }
}

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "domaincheckr": {
      "url": "https://domaincheckr.fly.dev/mcp"
    }
  }
}

Tools

Tool	Description
`check_domain`	Check if a single domain name is available for registration. Returns registrar, creation date, expiry, and nameservers for taken domains.
`check_domains_bulk`	Check up to 50 domain names at once. Returns per-domain results with summary counts.
`suggest_domains`	Generate and check domain name ideas for a keyword or business description. Creates 15 variations across .com, .io, .ai, .dev, .co and common prefixes/suffixes.

Example Prompts

Try asking your AI assistant:

"Is coolstartup.com available?"
"Check if these domains are available: acmecorp.com, acmehq.com, getacme.com"
"Find me a domain for a pet grooming business"
"I'm building a fintech app called PayFlow, find me a domain"

How It Works

DomainCheckr uses the RDAP protocol (Registration Data Access Protocol) to check domain availability in real time. RDAP is the modern replacement for WHOIS, standardized by the IETF.

Queries Verisign RDAP for .com/.net domains
Queries PIR RDAP for .org domains
Falls back to rdap.org for all other TLDs
HTTP 404 = available, HTTP 200 = taken

No scraping, no third-party APIs, no rate-limited services. Direct registry queries.

REST API

The same service is available as a REST API for building your own integrations or ChatGPT Actions.

Endpoint	Description
`GET /check/{domain}`	Check a single domain
`POST /check`	Bulk check (body: `{"domains": ["a.com", "b.com"]}`, max 50)
`GET /suggest?keyword=fintech`	Generate and check domain ideas
`GET /health`	Health check
`GET /docs`	Interactive API documentation
`GET /openapi.json`	OpenAPI spec (for ChatGPT Actions)

Base URL: https://domaincheckr.fly.dev

License

MIT