Tech Stack Checker

Tech Stack Checker: see what any website actually runs on

You land on a competitor's shop and wonder which platform it runs on, how many tracking pixels are watching, or whether the agency that just redesigned your own site quietly left three old marketing tools running underneath. Until now the answer meant installing a browser extension or paying for a BuiltWith subscription.

The Tech Stack Checker does the same job without an install and without an account. Paste the source code of any page, and the tool scans it for the fingerprints of CMS platforms like WordPress, Ghost or Wix, shop systems like Shopify, analytics tools like GA4 or Matomo, marketing pixels from Meta, TikTok or LinkedIn, tag managers, email and marketing automation tools like Klaviyo, Mailchimp or Brevo, consent banners, chat widgets, frameworks and CDNs.

What the check detects

• CMS and shop systems: WordPress, Shopify, Ghost, Wix, Webflow and more
• Analytics: Google Analytics 4, Matomo and similar measurement tools
• Marketing pixels: Meta, TikTok, LinkedIn and other ad networks
• Tag managers, email tools, consent banners, chat widgets: anything that gives itself away in the source
• Frameworks and CDNs: the technical foundation underneath

How the detection works

Every technology leaves traces in the delivered HTML: a particular script path, a meta generator tag, a data attribute, a class name in the markup. The Wappalyzer project built up these fingerprints over years, and after Wappalyzer retreated behind a paywall in 2023, the open community carried the database forward under the name webappanalyzer, now covering around 6,000 recognised technologies. The Tech Stack Checker runs entirely in your browser against that same database. The source code you paste never leaves your browser, there is no server reading along.

Frequently asked questions

Where do I get a website's source code?

Right-click the page, "View page source", or use the shortcut directly: Ctrl + U on Windows and Linux, Cmd + Option + U on a Mac, in Chrome, Firefox and Edge. In Safari, first enable the Develop menu under Safari → Preferences → Advanced, then use the same shortcut. Select all, copy, paste it here. Ten seconds, done.

Is this the same as the Wappalyzer browser extension?

The idea is related, the approach isn't. An extension has to be installed and has to visit the page itself to read it. The Tech Stack Checker needs neither: you copy the source of any page, whether it's a competitor's, a client's or your own, and get the result instantly, with no extension, no account and no cost.

Does the check really see everything a website uses?

No, and saying so plainly is part of the deal. The check only reads what's in the delivered HTML. Technologies that get loaded in purely at runtime through JavaScript often never show up in the source, so they slip past it. Signals that travel exclusively through HTTP headers, which happens with a handful of CDNs and servers, are also invisible to the tool, because it only ever gets the source code, never the headers. For CMS platforms, shops, pixels and most tools the source is still enough, because that's where they show themselves plainly.

Does my pasted source code end up anywhere?

No. Detection runs entirely in your browser against the locally loaded webappanalyzer database. Nothing is uploaded, stored or sent to a server.