DomainCheckr

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