Free Web Tools Online
Web infrastructure utilities: SSL checker, DNS lookup, WHOIS lookup, IP geolocation, website speed test, mobile-friendly test, sitemap generator, robots.txt generator.
7 free tools — browser-based, no sign-up required.
SSL Checker
Check SSL certificate status
Whois Lookup
Look up domain registration info
DNS Lookup
Look up DNS records
IP Lookup
Look up IP address information
Website Speed Test
Test website loading speed
Mobile Friendly Test
Test mobile compatibility
QR Code Reader
Read and decode QR codes
About FlexyPdf Web Tools
The web tools sit at the intersection of "I need to debug this in 30 seconds" and "I do not want to install a CLI just for one check". Each one performs a single network check against a domain or URL you provide, returns the result in a readable form, and surfaces the underlying technical detail that often matters for diagnosis (the full TLS certificate chain, the raw DNS records, the IP address class).
The SSL checker validates a certificate chain, flags upcoming expiration (especially the 30/14/7-day windows), reports the supported TLS versions and cipher suites, and warns about insecure protocols still enabled. DNS lookup queries A, AAAA, CNAME, MX, TXT, NS, and SOA records with the option to query against a specific resolver (Google 8.8.8.8, Cloudflare 1.1.1.1, or your default). WHOIS lookup returns registrar, registration and expiry dates, and contact information where it is published.
The website speed test measures First Contentful Paint, Largest Contentful Paint, Time to Interactive, and Cumulative Layout Shift using the Web Vitals API. The mobile-friendly test renders the URL at common phone viewport sizes and reports tap-target sizes, viewport configuration, and font legibility issues. Together these tools cover the questions that come up while shipping or debugging a web project: "is this HTTPS configured correctly", "is the DNS propagated yet", "why is this page slow on phones".
Who uses these tools
A few of the recurring use cases we hear about from FlexyPdf visitors.
Web administrators and devops
Verifying TLS certificate renewals, checking DNS propagation after a migration, diagnosing slow page load on production.
Front-end developers
Running mobile-friendly checks before launch, measuring Core Web Vitals against deployment goals.
Domain investors and registrars
Checking expiry dates and WHOIS data for domain portfolios.
Security researchers and IT staff
Auditing TLS configuration, identifying CNAME chains that could indicate subdomain takeover risk.
Frequently asked questions
Where does the WHOIS data come from?
WHOIS data is queried from a public WHOIS API. Some TLDs and registrars now redact contact details by default (GDPR/privacy regulations), so certain fields may appear as "redacted" or "private" — this is normal, not an error.
How accurate is the speed test?
It uses the standard Web Vitals API and reflects the load characteristics from the location and network conditions of the testing server. Real user metrics from your own analytics will differ — the test is best used as a relative comparison (before vs after a change) rather than an absolute benchmark.
Will running these tools against a domain alert the domain owner?
A standard DNS, WHOIS, or HTTPS request is the same kind of traffic that any browser makes when loading the site, so it is not "alerting" in any meaningful sense. The speed test sends a small number of requests but well within normal browsing.