33 free network & security tools — start with the Website Health Check, then dig into DNS, SSL, email, and headers. No signup required.
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Run a free security and health check on any website — SSL, DNS, email, speed, and more in one report.
Inspect SSL/TLS certificates — issuer, validity, protocol details.
Fetch HTTP response headers with a security header score.
Discover subdomains via DNS enumeration and certificate transparency.
Grade HTTP security headers (CSP, HSTS, X-Frame-Options) for any domain.
Analyze robots.txt for SEO and crawlability issues.
Decode JWT header and payload in your browser — no server upload.
Query A, AAAA, MX, TXT, CNAME, NS records in real-time.
Check DNS propagation across global resolvers.
Reverse DNS lookup with hosting provider detection.
Map any IP to country, city, ISP, ASN, and timezone.
Your public IP, geolocation, browser info, and connection details.
Check top 20 common ports on any host.
Domain registration details — registrar, dates, DNSSEC.
Quick reference for all HTTP 1xx–5xx status codes.
Measure TTFB, page load time, and size for any URL.
Instant screenshot of any website in desktop/tablet/mobile view.
Test regular expressions with match highlighting — runs in your browser.
Format, validate, and minify JSON instantly in your browser.
Encode text to Base64 or decode back — client-side only.
Encode and decode URLs and query strings in your browser.
Compare two texts side-by-side with unified diff view.
Live Markdown preview — write on the left, render on the right.
Convert between HEX, RGB, HSL, and HWB with contrast checker.
Generate placeholder text for mockups and typography testing.
Generate strong random passwords with customizable options.
Check password strength and entropy — nothing leaves your browser.
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes client-side.
Convert Unix timestamps to dates and back, any timezone.
Generate QR codes for URLs, text, WiFi, and email.
Start with the Website Health Check if you want one report covering SSL, DNS, email authentication, security headers, and speed. Use individual tools when you already know what to investigate — for example DNS Lookup after a migration, or MX Validator when inbound mail stops working.
Each tool page includes a written guide explaining what the check does, how to read results, and common failure patterns. For deeper reading, visit Learn — we publish original tutorials on domain health, SPF/DKIM/DMARC, HTTP headers, and pre-launch audits. All tools are free; no account required. Please use them only on domains and servers you own or are authorized to test (Terms of Service).