Ever visited a website and wondered "what's this built with?" Maybe you're scoping out a competitor, researching a potential client, or just genuinely curious about the tech behind a beautiful site.
There are tools for this — Wappalyzer, BuiltWith, WhatRuns. But they're either paywalled, require browser extensions, or show you more ads than data. I wanted something simpler: paste a URL, get the tech stack. No sign-up, no extension, no BS.
So I built StackRadar.
What It Does
StackRadar scans any website and detects 150+ technologies across 25 categories:
- •Frameworks — Next.js, React, Vue, Angular, Svelte, and more
- •Hosting — Vercel, Netlify, AWS, Cloudflare, Fly.io
- •Analytics — Google Analytics, PostHog, Mixpanel, Plausible, Heap
- •Payments — Stripe, Razorpay, PayPal, Paddle
- •CMS — WordPress, Shopify, Webflow, Contentful, Sanity
- •And 20 more categories — Auth, CDN, Build Tools, Monitoring, Email, Search, you name it
Each detection comes with a confidence indicator (High, Medium, Low) based on how many matching patterns were found.
How It Works Under the Hood
The detection engine is surprisingly straightforward. When you enter a URL, StackRadar:
- •Fetches the page server-side with a browser-like User-Agent
- •Reads HTTP headers —
X-Powered-By,Server,X-Vercel-Id,CF-Ray, etc. - •Scans the HTML for script sources, meta tags, link tags, and inline patterns
- •Matches against 150+ regex patterns — each technology has 2-4 unique signatures
- •Extracts version numbers where possible from script URLs and meta tags
For example, detecting Next.js is as simple as looking for /_next/static or __NEXT_DATA__ in the HTML. Stripe? Check for js.stripe.com. Tailwind CSS? Look for utility class patterns.
The tricky part is avoiding false positives. A word like "express" appears on tons of websites in regular text. So for server-side frameworks, we rely on headers (X-Powered-By: Express) rather than body content.
Features That Set It Apart
Compare Mode — Scan two sites side-by-side and see what they share vs. what's unique. Great for competitive analysis.
Scan History — Your last 10 scans are saved locally. One click to revisit any previous result.
Share & Download — Generate shareable links or download results as images. Perfect for reports or social sharing.
Version Detection — Where possible, StackRadar extracts version numbers (e.g., Next.js v14.1.0).
The Tech Stack (Yes, It Scans Itself)
- •Next.js 15 with App Router
- •Tailwind CSS for styling
- •Framer Motion for animations
- •Lucide React for icons
- •Vercel for hosting
- •Supabase for the waitlist backend
If you scan stackradar.rushiraj.me with StackRadar... it detects itself. Meta.
What's Next
StackRadar is free and always will be for basic scans. I'm working on a Pro tier with:
- •Bulk scanning — paste 50+ URLs, get a CSV
- •API access — for developers who want to integrate
- •Export as PDF/PNG — branded reports for agencies
- •90-day history — track how sites evolve over time
If that sounds useful, join the waitlist.
Try It
Head to stackradar.rushiraj.me and scan your favorite website. It takes about 3 seconds. Let me know what you find — I'm always adding new technologies to the detection engine.
The source code is on GitHub if you want to peek under the hood or contribute.