Tools to validate your website - Rocketeers app [ Rocketeers ](/) [Login](https://rocketeersapp.com/login) On this page Knowledge --------- Tools to validate your website ============================== ### [\#Performance](https://rocketeersapp.com/knowledge/performance) Before and after you launch, a handful of free tools tell you whether your site is secure, fast, and correctly configured. Here are the ones worth running. Published by [Mark van Eijk](https://rocketeersapp.com/author/mark-van-eijk) on June 30, 2026 · 2 minute read 1. [SSL and TLS](#content-ssl-and-tls) 2. [SSL Labs Server Test](#content-ssl-labs-server-test) 3. [Security headers](#content-security-headers) 4. [Security Headers and Mozilla Observatory](#content-security-headers-and-mozilla-observatory) 5. [Performance](#content-performance) 6. [PageSpeed Insights, Lighthouse, and WebPageTest](#content-pagespeed-insights-lighthouse-and-webpagetest) 7. [Markup and standards](#content-markup-and-standards) 8. [W3C validators](#content-w3c-validators) 9. [DNS and email](#content-dns-and-email) 10. [DNS and deliverability checkers](#content-dns-and-deliverability-checkers) 11. [Turn results into a launch list](#content-turn-results-into-a-launch-list) 12. [Let Rocketeers handle it](#content-let-rocketeers-handle-it) You can't fix what you can't see. After you've [set up a server](/how-to-host-your-own-website) and put a site live, these free tools grade the things that matter — TLS, security headers, performance, and markup — and tell you exactly what to improve. Run them at launch, then again whenever you make a significant change. [\#](#content-ssl-and-tls "Permalink")SSL and TLS ------------------------------------------------- ### [\#](#content-ssl-labs-server-test "Permalink")SSL Labs Server Test The gold standard for inspecting your HTTPS configuration. It grades your TLS setup from A+ down to F and flags weak protocols, missing chain certificates, and poor cipher choices. - **[SSL Labs](https://www.ssllabs.com/ssltest/)** — aim for an A+; here's [how to get there with Cloudflare](/a-plus-grade-ssl-using-cloudflare). A common failure it surfaces is an [incomplete certificate chain](/what-is-an-ssl-certificate-chain). You can also [check expiry yourself from the command line](/check-ssl-certificate-expiration). [\#](#content-security-headers "Permalink")Security headers ----------------------------------------------------------- ### [\#](#content-security-headers-and-mozilla-observatory "Permalink")Security Headers and Mozilla Observatory These scan the HTTP response headers your site sends and grade them — whether you set `Strict-Transport-Security`, a Content Security Policy, `X-Content-Type-Options`, and so on. - **[securityheaders.com](https://securityheaders.com)** — quick header grade. - **[Mozilla Observatory](https://observatory.mozilla.org)** — a broader security scan. More context in [optimizing web application security](/optimize-web-application-security). [\#](#content-performance "Permalink")Performance ------------------------------------------------- ### [\#](#content-pagespeed-insights-lighthouse-and-webpagetest "Permalink")PageSpeed Insights, Lighthouse, and WebPageTest These measure how fast your site loads for real users and give specific, prioritized fixes — render-blocking resources, uncompressed assets, slow server response. - **[PageSpeed Insights](https://pagespeed.web.dev)** — Google's Core Web Vitals report. - **Lighthouse** — built into Chrome DevTools, under the "Lighthouse" tab. - **[WebPageTest](https://www.webpagetest.org)** — detailed waterfall from multiple locations. If your server response is the bottleneck, it'll show up as a slow [time to first byte](/ttfb). General wins are in [optimizing website performance](/optimize-website-performance), and on the server side make sure you've [enabled gzip compression](/enable-gzip-compression-nginx). [\#](#content-markup-and-standards "Permalink")Markup and standards ------------------------------------------------------------------- ### [\#](#content-w3c-validators "Permalink")W3C validators Catch broken HTML and invalid CSS that can cause subtle rendering and accessibility issues. - **[W3C Markup Validator](https://validator.w3.org)** — HTML. - **[W3C CSS Validator](https://jigsaw.w3.org/css-validator/)** — CSS. [\#](#content-dns-and-email "Permalink")DNS and email ----------------------------------------------------- ### [\#](#content-dns-and-deliverability-checkers "Permalink")DNS and deliverability checkers If you send email from your domain, verify your SPF, DKIM, and DMARC records so your mail isn't flagged as spam. - **[MXToolbox](https://mxtoolbox.com)** — DNS, blacklist, and email record lookups. See [improving email deliverability](/improving-email-deliverability) for what those records should contain. [\#](#content-turn-results-into-a-launch-list "Permalink")Turn results into a launch list ----------------------------------------------------------------------------------------- Running the tools is step one; acting on them is step two. Pair this with the [website launch checklist](/website-checklist) so nothing slips through before you go live. [\#](#content-let-rocketeers-handle-it "Permalink")Let Rocketeers handle it --------------------------------------------------------------------------- Most of what these tools flag — weak TLS, missing security headers, no compression, an expired certificate — comes down to server configuration. Rocketeers provisions servers and sites with strong TLS, sensible headers, and compression on by default, and monitors your sites after launch, so you spend your time fixing the few things left rather than the basics. ### Subscribe to our newsletter Do you want to receive regular updates with fresh and exclusive content to learn more about web development, hosting, security and performance? Subscribe now! Fill in your email address to receive updates Subscribe #### More in [\#Performance](https://rocketeersapp.com/knowledge/performance) - [How to optimize server performance](https://rocketeersapp.com/knowledge/optimize-server-performance) - [How to optimize website performance](https://rocketeersapp.com/knowledge/optimize-website-performance) - [How to measure TTFB (Time To First Byte)](https://rocketeersapp.com/knowledge/ttfb) - [How to enable and configure OPcache for faster PHP](https://rocketeersapp.com/knowledge/enable-opcache-php) - [A complete guide to caching in Laravel](https://rocketeersapp.com/knowledge/laravel-cache) - [How database indexing works (with MySQL examples)](https://rocketeersapp.com/knowledge/database-indexing) [View all 13 articles →](https://rocketeersapp.com/knowledge/performance)