Domain signals for software and agents.

Authentication

Create a key in your developer account, then send it in the HTTP Authorization header. Keys are shown once and cannot be recovered.

Authorization: Bearer nt_live_…

Domain overview

GET https://api.nerdtools.co.uk/v1/domain/overview?domain=example.com

The overview runs a useful default bundle. Select checks with &checks=dns,dnssec,tls_certificate,security_headers. A composite request consumes one quota unit.

REST endpoints

DNS + email: /dns/records, /dns/caa, /dns/dnssec, /email/spf, /email/dmarc, /email/mx, /email/dkim

Domain + TLS: /domain/overview, /domain/registration, /domain/whois, /tls/certificate, /tls/protocols

Web + SEO: /web/security-headers, /web/redirects, /web/robots, /web/sitemap, /web/security-txt, /web/llms-txt, /web/metadata, /web/schema, /web/indexation, /web/seo, /web/broken-links, /web/performance

IP + network: /ip/info, /ip/reputation, /ip/blacklist, /network/ping, /network/ports

See the OpenAPI description for parameters and response definitions.

Port scans and quota

GET https://api.nerdtools.co.uk/v1/network/ports?host=example.com&ports=80,443,8443

One port-scan request consumes one API quota unit. Each request may contain up to 25 unique TCP ports.

Response envelope

{
  "ok": true,
  "data": { "domain": "example.com", "records": [] },
  "error": null,
  "meta": { "request_id": "…", "api_version": "v1", "plan": "free" }
}

Errors use the same envelope with ok: false, a stable error.code, and an HTTP status such as 401, 422, 429 or 502. Limit state is returned in the standard-style RateLimit-* headers.

MCP server

Connect a Streamable HTTP MCP client to https://api.nerdtools.co.uk/mcp and provide the same API key as a Bearer token. The MCP server exposes the complete read-only diagnostic catalog, including inspect_domain, TLS, web, SEO, IP, reputation, ping, and bounded port scanning.

{
  "url": "https://api.nerdtools.co.uk/mcp",
  "headers": {
    "Authorization": "Bearer nt_live_…"
  }
}

Each MCP invocation consumes one quota unit, including inspect_domain and scan_ports.

Plans and limits

Free and Pro include the complete tool catalog. Pro raises the monthly and per-minute limits for production integrations; upgrades are managed from the developer account.

Explore the developer platform · Download the OpenAPI description