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Website Checker Tools

Check any website’s speed, availability, SSL certificate and technology stack in seconds — no account or browser extension needed.

Website Speed TestMeasure your site’s mobile and desktop speed with Google Lighthouse and see your score, Core Web Vitals and what to fix first.Internet Speed TestMeasure your real download and upload speed, ping and jitter, and see whether your connection is good enough for streaming, gaming and video calls.Is It Down?Find out in seconds whether a website is down for everyone or just for you, with the exact HTTP status code and response time.HTTP Header CheckerSee the full HTTP response headers of any URL, hop by hop, and find out which security headers are missing.Redirect CheckerTrace a URL’s full redirect path hop by hop and see the status code, timing and final destination of each step.SSL CheckerCheck whether a domain’s SSL certificate is valid, who issued it, when it expires and which hostnames it covers.Website Technology CheckerEnter any URL to see which CMS, frameworks, analytics and ad tags, CDN and server the website uses.Broken Link CheckerScan a page’s links and instantly see which ones return 404, server errors or redirects.

When a site will not load

Start with the “is it down” checker to see whether the problem is just on your side or affects everyone. If the site is reachable from outside, run the internet speed test to check your own connection. If the server returns an error, the HTTP header checker shows the exact status code and response headers, and the redirect checker traces every hop to reveal loops or long chains. For browser security warnings, the SSL checker verifies the expiry date and certificate chain.

Performance and maintenance checks

The website speed test measures load time and Core Web Vitals and points to the resources that slow the page down. The broken link checker crawls the links on a page and lists the ones returning 404 or other errors; broken links frustrate visitors and waste search engine crawl budget. Running both checks after a redesign, a CMS update or a migration catches problems before your users do, and repeating them monthly on key pages is a good habit.

Looking under a competitor’s hood

The website technology checker detects which CMS, e-commerce platform, JavaScript framework, analytics and hosting services a site uses. It is useful when you are planning a new site and want to see what similar businesses chose, or when you need to understand a client’s current setup before writing a proposal. Detection relies on traces in the page’s public code and headers, so server-side software and deliberately hidden technologies may not appear in the results.

Related guides

Core Web Vitals explained: LCP, INP and CLSCore Web Vitals are Google's three metrics for real-world page experience: loading, responsiveness and visual stability. Here is what each means and how to fix it.Internet speed explained: what your speed test results meanA speed test gives you four numbers. Here's what each means, how much you actually need for streaming, gaming and video calls, and what to do when it's slower than you pay for.301 vs 302 redirects: which one should you use?Use a 301 (or 308) when a URL has moved for good and a 302 (or 307) when the move is temporary. The details below cover SEO, chains, loops and server configuration.How to speed up your website: what actually makes a differenceMost slow websites are slow for the same few reasons. Measure first, fix the biggest bottleneck, then repeat. Here is the order that pays off fastest.What is an SSL certificate, and how do you fix SSL errors?An SSL (really TLS) certificate lets browsers verify your site and encrypt the connection. Getting one is free; keeping it valid and configured correctly is where sites trip up.Is the website down for everyone or just me?Before you panic or call your host, spend two minutes working out where the problem is. The cause is usually DNS, an expired certificate, the server, or your own connection.

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