All tools · page 279
6,901 free tools across 25 categories. Tools marked with a lightning bolt are ready to use right now.
Automatically discover RSS/Atom feeds on any site — checks page headers and all standard feed locations.
Discover every favicon and touch icon a site publishes, with sizes — grab the best one for embedding.
Fetch and analyze any site's robots.txt: rules, blocked paths, sitemap declarations and common mistakes.
Inspect the start-of-authority record: primary NS, admin, serial and timers.
Check which certificate authorities are allowed to issue certificates for a domain.
One lookup that returns A, AAAA, CNAME, NS, MX, TXT, SOA and CAA records together.
Resolve an IP address back to its hostname — essential for mail server setup.
Fetch and decode a domain's SPF record: every mechanism explained, plus policy strength verdict.
Read and explain a domain's DMARC policy: p= level, reporting targets and alignment.
Verify every MX record actually resolves — catch misconfigured mail routing before senders bounce.
Check how many days are left before a site's certificate expires — catch renewals before browsers block you.
Follow every hop of a URL's redirect chain with status codes and timing — kill long chains that slow users down.
Test whether a resource allows cross-origin requests and inspect its CORS policy.
Check every cookie a server sets for Secure, HttpOnly and SameSite flags.
Measure response time across 3 runs with a speed verdict — from a real server, not your ISP.
Expand any short link (bit.ly, t.co…) to its true destination before you click it.
Test whether a server compresses responses and compare gzip vs brotli sizes.
Identify Cloudflare, Vercel, CloudFront, Fastly or Akamai in front of any website.
Grade a site's security headers (HSTS, CSP, X-Frame-Options and more) out of 100 with fix hints for every miss.
Inspect the CSP header that controls which scripts a page may load.
Check clickjacking protection (X-Frame-Options / frame-ancestors).