FerrLens is a set of web tools for checking a site from the outside: SEO and performance, DNS, email authentication, HTTP and security headers, link checking. Open a tool, enter a domain or URL, read the result. Every live tool is listed on the home page.

Anonymous use

No account is needed. Every tool works without signing in, and each one is backed by a JSON endpoint under api.ferrlens.com. Anonymous requests share a per-IP budget, described in Rate limits.

What an account adds

Signing in goes through your FerrLabs account at auth.ferrlabs.com. Today the account only identifies you: it does not change rate limits or how long share links live. Every tool and endpoint behaves the same signed in or out.

API keys, per-account quotas, history and batch runs are on the pricing page but are not available yet. They get documentation when they ship.

Where to start

• API: every endpoint, grouped by what it checks, with request and response shapes.
• Rate limits: the per-IP budget and what a 429 looks like.
• Share links: publish a snapshot of a result, and take it down again.