See which tools a SaaS runs on.
Free check: enter any SaaS homepage and see the payment processor, analytics, error tracker, email provider and framework it loads in the browser.
One request to the page you typed. No crawling, no account.
- 01
Paste a homepage
Any SaaS, including a competitor's. Only that one page is fetched.
- 02
Read the markup
Script hosts, globals, meta tags and response headers are matched against about fifty known tools.
- 03
See the stack
Payments, analytics, errors, support, email, auth, framework and hosting — plus what came back empty.
About Stack
Everything a site loads in your browser is public. The payment script, the analytics snippet, the error tracker, the framework's own fingerprints — they are all in the HTML, which is why a competitor's stack is never really a secret.
Stack fetches one page — the one you enter, nothing else — and reports what it recognises. No crawling, no login, no account.
Questions
- How does it detect the tools?
- By fingerprinting the HTML the page returns: script hosts, global variables, meta tags and framework markers. Anything loaded later by JavaScript in a real browser is invisible to it.
- Why does it miss things I know are there?
- Server-side tools leave no trace in the HTML, and tag managers hide everything behind one script. A clean result means “nothing recognisable in the markup”, not “nothing installed”.
- Is it legal to check a competitor's stack?
- You are reading a public page the same way a browser does, once. That is what every browser extension doing this has always done.
Stack answers one question. Seiton answers the rest every morning.
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