Developer tools hub

Free diagnostics tools focused on real production debugging: redirects, DNS records, SSL, caching, headers, and uptime behavior.

Live tools

Redirect Checker

Inspect redirect hops, final URL, and status behavior.

Domain IP Lookup

Compare DNS A/AAAA records with runtime-resolved IP addresses.

Cache Header Check

Interpret Cache-Control, ETag, Expires, and compression signals.

CORS Checker

Test simple and preflight CORS behavior by origin and method.

Port Reachability Check

Probe TCP port reachability and latency for target hosts.

Robots + X-Robots Checker

Validate robots.txt, meta robots, and X-Robots-Tag directives.

Canonical Checker

Detect missing or conflicting canonical link hints.

Security Headers Scorecard

Score key security headers and flag missing protections.

CSP Linter

Inspect Content-Security-Policy and flag risky directives.

HSTS Preload Checker

Check Strict-Transport-Security preload readiness hints.

security.txt Checker

Validate /.well-known/security.txt presence and fields.

SPF Checker

Validate SPF TXT records and common policy issues.

DMARC Checker

Validate DMARC policy records and baseline tags.

DKIM Checker

Validate selector-based DKIM DNS records.

Open Graph + Twitter Checker

Check social preview metadata for share cards.

HTTP Method Checker

Inspect OPTIONS Allow and CORS method declarations.

Protocol Checker

Show HTTP version and ALPN negotiation details.

Uptime Check

Check DNS, TCP, TLS, and HTTP reachability in one report.

SSL Checker

Validate certificate trust chain and expiration windows.

Headers Checker

Audit security headers and redirect chains.

DNS Lookup

Query A, AAAA, CNAME, MX, TXT, NS, and CAA records.

HTTP Deep Check

Review protocol, cookies, cache, compression, and special paths.