# Checking a website: the 10 tools we use to test every website, before and after go-live > URL: https://4eck-media.de/en/blog/checking-a-website-the-10-tools-we-use-to-test-every-website-before-and-after-go-live/ > Language: en > Description: How do you actually check whether a website is good? I get this question regularly: from clients, from career changers, sometimes from colleagues. The honest answer is unspectacul… --- How do you actually check whether a website is good? I get this question regularly: from clients, from career changers, sometimes from colleagues. The honest answer is unspectacular: we measure. With ten tools, almost all of them free, that anyone can start using today. There is no secret agency toolbox. There are only tools you know about, and the discipline to apply them to every project. That is exactly the difference between a professional presence and an after-hours project: not access to the tools, but the routine. A hobbyist checks when something stands out. We check before anything stands out: every project, every time, against fixed minimum values. What we check is set out in our [pre go-live checklist](https://4eck-media.de/en/blog/website-checklist-before-go-live-what-we-check-before-a-website-is-allowed-to-go-online/) and the [checklist for the time afterwards](https://4eck-media.de/en/blog/website-launch-checklist-what-separates-quality-from-botched-work-after-go-live/). What we check it with is set out here. **The short version** No time for ten separate tools? Before and after every go-live we check a website for loading speed, SEO and indexability, accessibility, technical security, correct link previews and structured data for search engines and AI systems. To do so we work with fixed minimum values and document deliberate exceptions – instead of relying on the impression that it “looks good”. **Jump straight to:** - [**Performance**](#heading-0) – we measure loading time and Core Web Vitals so that visitors do not bounce and the website meets Google’s requirements. - [**SEO and indexing**](#heading-1) – we check crawlability, metadata, structure and indexing status so that search engines find all the important pages and classify them correctly. - [**Accessibility**](#heading-2) – we test WCAG criteria and typical usability barriers so that as many people as possible can use the website without difficulty. - [**Security**](#heading-3) – we check security headers and technical protective measures so that known attack surfaces are reduced. - [**Link preview**](#heading-4) – we check Open Graph data so that shared links appear complete and professional in social networks and messengers. - [**Structured data and AI**](#heading-5) – we validate schema markup and machine readability so that search engines and AI systems can reliably understand and cite the content. **Would you like to know where your website stands?** [Have your website checked by 4eck Media →](https://4eck-media.de/en/contact/) Measure, don't opine - Every one of these tools is publicly available, most of them free of charge - The difference lies not in the tool but in the routine: every project, every time, against fixed minimum values - Numbers replace debates about taste: 94 points are 94 points - Before go-live we test the building site; after go-live we prove it on the real domain ![Infographic showing ten tools that 4eck Media uses to check websites before and after go-live](https://4eck-media.de/wp-content/uploads/2026/07/website-testing-tools-infographic-brand-english-16x9-2.avif "Checking a website: 10 tools for performance, SEO and quality") ## Performance: Google PageSpeed Insights A slow website loses visitors before they have read the first sentence. And Google now rates the user experience with hard metrics, the Core Web Vitals. That is why every quality check we run starts with speed. [PageSpeed Insights](https://pagespeed.web.dev/) is the reference tool for this: free, straight from Google, and it combines lab measurements with real user data from the Chrome UX Report. We measure mobile and desktop separately (mobile is the more honest test) and look behind the score at the three core values: LCP (when is the largest element visible?), INP (how quickly does the page respond?) and CLS (does the layout jump while loading?). Our threshold: at least 90 points on mobile, with 94 and above as the target. The buffer is deliberate, because after handover someone will eventually upload an image that is too large. The single most common finding: exactly that kind of image in the hero area. ![PageSpeed Insights for Raumfreude Rostock: 93 performance, 100 accessibility, 96 best practices and 100 SEO](https://4eck-media.de/wp-content/uploads/2026/07/raumfreude-rostock-pagespeed-insights-performance-monitor-mockup.avif "PageSpeed Insights for Raumfreude Rostock: 93 points on mobile") **PageSpeed analysis of the website built by 4eck Media for the interior fitter Raumfreude Rostock.** ## SEO and indexing: Seobility and Google Search Console The best content is worthless if search engines cannot capture it cleanly. These two tools answer two different questions: what can crawlers find on the website, and what does Google actually make of it? [Seobility](https://www.seobility.net/) crawls the entire website and sorts the findings into three groups: technology & meta, structure and content. Its strength is coverage: a crawler forgets no page and overlooks no series. Duplicate titles, missing meta descriptions, broken links, orphaned pages, service pages buried too deep. You see all of that in the report, not by eyeballing it. On one of our recent projects the technology section stood at 98 per cent, and even so the final two per cent still held two problematic descriptions and three missing alt attributes. That is exactly what the tool is for. Individual checks are free; the regular full crawl is part of the paid plan and is one of the most self-evident investments we make. ![Seobility audit for Schloss Torgelow with a 94 % on-page score, 95 % technology and meta, 99 % structure and 89 % content](https://4eck-media.de/wp-content/uploads/2026/07/schloss-torgelow-seobility-onpage-score-website-audit-laptop-mockup.avif "Seobility website audit for Schloss Torgelow: 94 % on-page score") **Seobility audit of the website built by 4eck Media for Schloss Torgelow.** The [Google Search Console](https://search.google.com/search-console) is not a testing tool in the narrow sense but something more valuable: the only place where Google tells you directly how it sees your website. Free, yet never set up by a surprising number of websites. After every launch we use the URL inspection with a live test (can Google fetch the page, may it enter the index, which canonical URL is recognised?), submit the sitemap and watch the indexing reports and 404 notices in the weeks that follow. Anyone who does not use the Search Console is voluntarily giving up feedback from the most important search engine in the world. ## Accessibility: AccessibilityChecker and AccessScan Since the German Accessibility Strengthening Act came into force on 28 June 2025, accessibility has been a legal obligation for many services. For us it was a professional one long before that: a website that some visitors cannot operate is not a finished website. And because no scanner sees everything, we use two. [AccessibilityChecker.org](https://www.accessibilitychecker.org/) delivers a WCAG audit in a few seconds with a concrete list of errors: missing alternative texts, contrasts that are too weak, unlabelled form elements, empty links. The findings are precise enough to hand straight to development as a task list. ![AccessibilityChecker audit for mobiblox.de with 90 out of 100 points, compliant status and zero critical accessibility issues](https://4eck-media.de/wp-content/uploads/2026/07/mobiblox-accessibilitychecker-wcag-audit-90-tablet-mockup.avif "AccessibilityChecker audit for Mobiblox: 90/100 and no critical errors") **Accessibility check of the website built by 4eck Media for Mobiblox.** [AccessScan](https://accessibe.com/accessscan) is our cross-check. Two scanners with different rule sets find different things: one scanner’s blind spot is the other’s hit. What neither can do: judge whether an alt text is meaningful or a focus order logical. That is why every scan comes with the manual steps: navigate without a mouse, follow the focus, test zoom. How we plan accessibility in from the start is set out on our page about [accessible websites](https://4eck-media.de/en/competencies/accessibility-for-your-websites-web-design-agency/). ![AccessScan check for wildpark-mv.de with the result "This page is Accessible" and an accessibility score of 94](https://4eck-media.de/wp-content/uploads/2026/07/wildpark-mv-accessscan-barrierefreiheit-score-94-monitor-mockup.avif "AccessScan for Wildpark-MV: accessible website with a score of 94") **AccessScan of the website built by 4eck Media for Wildpark-MV.** ## Security: SecurityHeaders.com Security headers are rules the server passes to every browser: enforce HTTPS, forbid third-party embedding, limit script sources. Visitors see nothing of them. Attackers do, and immediately, because missing headers can be read from the outside like an open window. [SecurityHeaders.com](https://securityheaders.com/) checks the most important headers in seconds and awards a grade from A+ to F. We want at least an A, but not at any price: an over-eager Content Security Policy that incidentally blocks the payment provider or the consent manager is not a security measure but a new bug with a better grade. That is why our rule is: after every header change the website gets a functional test, with a look at the browser console. The most common finding on first checks: no HSTS set at all. ![Security headers test for bolzakademie.de with an A+ rating and six active protective headers on a desktop monitor](https://4eck-media.de/wp-content/uploads/2026/07/bolzakademie-security-headers-a-plus-sicherheitscheck-monitor-mockup.avif "Security headers for Bolzakademie: A+ in the security check") **Security check of the website built by 4eck Media for Bolzakademie.** ## Link preview: opengraph.xyz First contact with a website increasingly happens not in the browser but in WhatsApp, LinkedIn or Teams: as a shared link. Whether an appealing card with an image and a title appears there, or a grey box, is decided by the Open Graph data. Why that matters we described in detail in the [pre go-live checklist](https://4eck-media.de/en/blog/website-checklist-before-go-live-what-we-check-before-a-website-is-allowed-to-go-online/). Here is the tool for it. [opengraph.xyz](https://www.opengraph.xyz/) shows, for any URL, how the preview looks on Facebook, LinkedIn, X and in messengers, without having to post the link somewhere as a test. We use it constantly: after every relaunch, for every important landing page, for every new blog article. Typical findings: an og:image still pointing at the development domain, a truncated title, a missing preview image in the 1200 by 630 pixel format. The test takes a minute and decides the first impression of every shared recommendation. ![Open Graph analysis for raumfreude-rostock.de with social media preview, zero errors, zero warnings and twelve meta tag checks passed](https://4eck-media.de/wp-content/uploads/2026/07/raumfreude-rostock-opengraph-social-media-vorschau-meta-tags-display-mockup.avif "Open Graph preview for Raumfreude Rostock: 12 meta tag checks passed") **Open Graph check of the website built by 4eck Media for Raumfreude Rostock.** ## Machine readability and AI: Schema Validator, Rich Results Test, isitagentready Websites have long since stopped being read only by humans. Search engines, AI assistants and agents have to understand who offers what here, and for that they need structured data and clear content. Three tools, three different questions. The [Schema.org Validator](https://validator.schema.org/) checks the grammar: is the markup syntactically correct, are the types and properties valid, does the graph hold together? A must after every relaunch, because old staging URLs and outdated details survive in schema data remarkably often. One thing matters here: valid does not yet mean true. Whether the telephone number in the markup matches the one in the footer is something no validator checks. That remains manual work. ![Schema.org Validator for 4eck-media.de with 20 detected structured data items, zero errors and zero warnings](https://4eck-media.de/wp-content/uploads/2026/07/schema-org-validator-4eck-media-20-items-ohne-fehler-monitor-mockup.avif "Schema.org Validator for 4eck Media: 20 items with no errors") **Schema.org check of our own website, developed by 4eck Media.** The [Rich Results Test](https://search.google.com/test/rich-results) answers the second question: which of it does Google understand as a basis for special search presentations? Google supports only a subset of all schema types: FAQ, articles, breadcrumbs, reviews and a few more. Together the two tools give the full picture: first the grammar, then the effect. [isitagentready.com](https://www.isitagentready.com/) is the newest tool on our list and answers the question that is becoming important right now: can an AI agent work with this website? Among other things it checks whether AI crawlers are allowed in, whether content is structured in a machine-readable way and whether the website contains clear, quotable statements. Anyone who has grasped that recommendations are increasingly issued by ChatGPT, Gemini and Perplexity no longer leaves this check until last by choice. The strategic side of it is set out in our [GEO framework for AI visibility and recommendations](https://4eck-media.de/en/blog/the-4eck-geo-framework-for-ai-visibility-ai-recommendations/). ## Ten tools, one principle None of these tools is a secret, and almost all of them are free. Even so, using them consistently is what separates the professional website from the after-hours project, because measuring changes the conversation. “It looks fine” becomes a value, a date, a piece of evidence. “That should be all right” becomes a documented exception or a fixed error. If you want to check for yourself: the order and all the checkpoints are set out in our [pre go-live checklist](https://4eck-media.de/en/blog/website-checklist-before-go-live-what-we-check-before-a-website-is-allowed-to-go-online/) and the [checklist for the time after go-live](https://4eck-media.de/en/blog/website-launch-checklist-what-separates-quality-from-botched-work-after-go-live/). These ten tools are the instruments for it. And if you would rather hand the check over: you can reach us directly via the [contact page](https://4eck-media.de/en/contact/), ideally with the measurements from your existing website. Then we are not talking about taste, but about numbers. The toolbox keeps growing, by the way: for multilingual projects we have documented how we [translate WPML with AI](https://4eck-media.de/en/blog/translating-wordpress-with-ai-fast-cheap-and-without-the-wpml-frustration-our-complete-workflow/), on the same principle: measure, check, prove. ## Frequently asked questions about our test tools Are these tools free? For the most part, yes. PageSpeed Insights, the Search Console, the Schema.org Validator, the Rich Results Test, opengraph.xyz and the basic scans from AccessibilityChecker, AccessScan, SecurityHeaders.com and isitagentready.com cost nothing. Seobility offers free individual checks; the complete, regular crawl of an entire website is part of the paid plan. To get started, the free tier is enough almost everywhere. Are these automated tests enough to guarantee a good website? No, and we do not claim they are. The tools reliably find what can be measured: technical errors, missing details, slow delivery. Whether an alt text is meaningful, a navigation logical or a text convincing is still decided by a human. That is why we combine every automated check with manual controls, as described in our two checklist articles. When should you use these tools: before or after go-live? Both, and deliberately twice. Before go-live we check the finished build; after go-live we repeat the most important measurements on the real domain, because that is where the CDN, caching, consent manager and real mail servers come into play. The order and all the checkpoints are set out in our before-live and after-live checklists. Which values count as good? Our guide values: PageSpeed mobile at least 90, with 94 and above as the target. SecurityHeaders.com at least an A. In the accessibility scans and the schema validator: zero unjustified errors. And in the Search Console: no unexplained indexing exclusions. More important than any single number, though, is that deliberate exceptions are documented rather than tacitly accepted.