Website diagnostics

Cache analysis

Check Cache-Control, Age, ETag and cache headers for a public website. View the results and optionally compare them from a second location.

Free pilotNo account neededPublic websites only
Mail options

Use the selector from your mail provider or s= in DKIM-Signature. Enter the signing domain from d= as the website domain. No email is sent.

Checking…

Use public URLs without passwords or private tokens. Reports expire after one hour. Up to ten checks per hour.

What this check tells you

Inspect response headers that describe caching and resource validation.

Interpretation and next steps

Review cache directives for this response. Header presence does not demonstrate actual cache reuse.

How to read this result

Explore the tools

HTTP/2 / HTTP/3 checker

Test actual HTTP/2 and HTTP/3 connections to your HTTPS URL.

WHOIS / RDAP lookup

Look up public domain registration data, registrar, dates and nameservers.

Ping test

Measure ICMP replies from a public host with a bounded four-packet test.

Traceroute

Inspect a bounded network route to a public host.

SSL / TLS checker

Check certificate trust, hostname coverage and expiry before visitors encounter a warning.

Gzip & Brotli checker

See the actual content encoding and response sizes for identity, Gzip and Brotli requests.

Redirect checker

Follow HTTP redirects, inspect status codes and identify loops or unnecessary hops.

HTTP headers checker

Inspect the headers returned by your website, including caching and content type.

Security headers checker

Review browser security headers and understand what each policy is intended to protect.

DNS lookup

Look up A, AAAA, MX, NS, TXT and CAA records with clear, readable output.

Website availability checker

Check HTTP connectivity and response timing, with an optional comparison from a remote server.

Mail DNS

Inspect SPF, DMARC and the DKIM record for a supplied selector at the submitted hostname.

Email test

Send an email to a temporary address. Check SPF, DKIM, DMARC, the sending server and message structure.

DNSSEC

Observe whether the selected DNS resolver confirms DNSSEC validation.

robots.txt

Read robots.txt and simulate Googlebot and Bingbot rules for the exact submitted URL.

Sitemap

Fetch one sitemap XML document and inspect its type, entry count and sample URLs.

Indexability

Inspect the returned HTML title, description, canonical and indexing directives.

Open Graph

Inspect Open Graph tags that describe the page for link previews.

Cache analysis

Inspect response headers that describe caching and resource validation.

How this pilot works

Bounded HTTP, TLS and DNS checks. No sign-in, full-site crawling or vulnerability exploitation. Up to 70 seconds per location, plus queue time.

Results are observations, not security certification or proof of Google indexing. Only one sitemap is inspected. DKIM checks DNS publication, not message signatures.

Reports and URLs expire after one hour. Cookie values and page bodies are not stored in reports. Anyone with a report ID can read it until expiry. Rate limits use temporary keyed IP hashes; infrastructure logs are separate. Display preferences stay in this browser.

A name for your next idea

Give your website, home server or next project a memorable address: yourname.uk.app. Choose your name and check availability before registering.

Find your name

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