WhatStack

See what a site is built with — React, Next, Remix, Vue, Angular, TanStack, and more. Fully local stack detection.

WhatStack tells you what a website is built with — instantly, on the page you’re already viewing. Open any site, click the toolbar icon, and get a clear breakdown of its frontend stack: frameworks, UI libraries, data tools, auth and payments, analytics, and more. No DevTools digging. No guesswork from the marketing page. No account. WHY INSTALL IT • Research competitors and products — learn real stacks, not job-post fluff • Speed up technical interviews, sales calls, and client discovery • Learn by example — see how production sites actually ship • Share findings with your team as text, Markdown, or JSON • Stay private — detection runs only on your device; nothing is uploaded for scanning WHAT YOU GET • A one-line headline of the core stack (e.g. Next.js + React + Tailwind) • Categories with confidence (high / medium / low) so weak signals don’t look like facts • Expandable evidence for every hit — why WhatStack thinks that library is present • A badge on the toolbar as you browse, with a deeper scan when you open the popup WHAT IT DETECTS (examples) • Frameworks: React, Next.js, Remix, Vue, Nuxt, Angular, Svelte/SvelteKit, TanStack Start, jQuery, Solid • Architecture: Module Federation, single-spa, qiankun, SystemJS • Build: Webpack, Vite, Parcel, Turbopack • Data: TanStack Query/Router/Table/Form/Virtual, Apollo, SWR, Axios • UI: Tailwind, Bootstrap, MUI, Emotion, styled-components • Auth & payments: Auth0, Clerk, Firebase, Stripe, Razorpay • Observability: Sentry, Datadog, New Relic, LogRocket • Analytics & hosting: Google Analytics, Segment, Vercel, Cloudflare, and more BUILT FOR TRUST WhatStack analyzes publicly visible page signals on your machine only. It does not upload page content or stack results, does not sell data, and has no ads. If a result looks wrong, “Wrong?” opens a draft GitHub issue you review and submit yourself — site origin only, never the full URL. Note: some minified production apps leave no fingerprints. A miss does not always mean the library is absent; a mention in marketing copy alone is not treated as a real install. HOW TO USE 1. Install WhatStack 2. Visit any website 3. Click the WhatStack icon 4. Read the headline and categories 5. Optional: copy results or report a miss Single purpose: identify the frontend technology stack of the web page you are viewing.