API reference

API.

Every public FerrLens tool has a JSON endpoint under api.ferrlens.com. POST your input, get structured JSON back. Anonymous requests are rate-limited per IP; an account token lifts the quota and unlocks batch endpoints.

Authentication

Anonymous calls work out of the box with a low per-IP rate limit. Pass an API token as a Bearer header for a real quota.

curl -X POST https://api.ferrlens.com/v1/dns/lookup \
  -H 'authorization: Bearer ferrlens_xxx' \
  -H 'content-type: application/json' \
  -d '{"domain":"example.com"}'

Endpoints

Each tool maps to a single POST endpoint. Request and response bodies are JSON.

Lighthouse scorePOST /v1/seo/check

SERP previewPOST /v1/web/meta

Sitemap validatorPOST /v1/seo/sitemap

Robots.txt analyzerPOST /v1/seo/robots

Meta tag inspectorPOST /v1/web/meta

Broken link checkerPOST /v1/link-check

OG card previewPOST /v1/web/og-preview

Email verifierPOST /v1/email/verify

SPF / DKIM / DMARCPOST /v1/email/spf-dmarc

Blacklist checkerPOST /v1/email/blacklist

DNS lookupPOST /v1/dns/lookup

CT log searchPOST /v1/web/ct-search

Reverse DNSPOST /v1/dns/reverse

HTTP header inspectorPOST /v1/http/headers

Security headersPOST /v1/http/sec-headers

CORS testerPOST /v1/web/cors

Mixed content scannerPOST /v1/web/mixed-content

Rate limits

Anonymous IPs share a low burst quota. A 429 response carries a Retry-After header. Sign in for a per-account quota.