# How to Detect the Tech Stack of Any Website (2026 Guide)

> Five reliable methods to identify a site's frameworks, hosting, analytics, and CRM, from a 10-second lookup to a programmatic API pull across thousands of domains.

Canonical URL: https://the-web-radar.com/blog/how-to-detect-tech-stack-of-any-website
Published: 2026-04-23
Modified: 2026-04-23
Author: Web Radar Team

---


<AnswerBox>
  The fastest way is a **free domain lookup tool** (like Web Radar's homepage). For bulk or programmatic detection across thousands of domains, use an API, or buy a ready-made dataset filtered by technology.
</AnswerBox>

Websites leak their tech stack in five places: HTML source, HTTP headers, cookies, loaded scripts, and meta tags. If you know where to look, you can identify a site's stack in under a minute. This guide walks through five methods, from zero-effort to programmatic.

## Method 1: The free lookup tool (10 seconds)

The fastest way is a hosted detector.

- Paste any domain into [Web Radar's homepage](/). No signup, unlimited lookups.
- You get the full stack: hosting, CDN, CMS, frameworks, analytics, payments, CRM.

<Callout type="tip" title="When this is enough">
  You're researching one or two prospects, or sanity-checking a competitor's migration rumor. Don't over-engineer it.
</Callout>

## Method 2: Browser extension (manual, still free)

Wappalyzer's extension still works, though bulk export has moved behind a paywall. Install, visit a page, click the icon. Good for manual sales research on 5–20 domains a day.

**Limitation**: you can only inspect what you personally visit. No bulk, no CSV.

## Method 3: Developer tools (for engineers)

If you want to verify a detector's output, or learn what signals drive the guess:

```bash
curl -I https://example.com
```

Headers like `Server`, `X-Powered-By`, `X-Generator`, `Set-Cookie` (look for `PHPSESSID`, `JSESSIONID`, `_shopify_*`), and `Link: <*>; rel=preload` reveal most of the stack. Then `view-source:` on the page: meta tags, script src attributes, and CSS classnames fill in the rest.

This is the layer Wappalyzer's rules pattern-match. The [detection patterns are open-source](https://github.com/enthec/webappanalyzer): 7,200+ rules, MIT-licensed.

## Method 4: API for programmatic detection

When you need to run detection across hundreds of domains programmatically:

<KeyFacts>
  <Fact label="Input" value="Domain or URL" />
  <Fact label="Output" value="JSON: tech list with versions + categories" />
  <Fact label="Rate limit" value="Tier-based (free/pro/enterprise)" />
  <Fact label="Auth" value="API key in X-API-Key header" />
</KeyFacts>

Every serious technographics vendor has one. Web Radar's is priced per-call on paid tiers, with a free allowance for evaluation.

## Method 5: Buy a pre-filtered dataset

When you don't want to crawl anything at all. You want the list.

Instead of "detect tech on domain X," flip the question: **"give me every domain running tech Y, in country Z, with N+ employees."** That's what [Web Radar's datasets](/datasets) answer. One checkout, one CSV, done.

<Callout type="warn" title="Accuracy caveat">
  No detector is 100%. Server-side rendering, CDN caching, and minified bundles can mask signals. Expect 85–95% accuracy on common stacks, less on obscure or internal tools.
</Callout>

## Which method should you pick?

- **One-off research** → Free lookup tool.
- **Continuous manual checking** → Browser extension.
- **Programmatic detection across a crawl you already have** → API.
- **Targeted lead generation** → Pre-filtered dataset.

For 90% of B2B teams, it's the last option. Detecting tech stacks yourself is a solved problem. The real work is deciding what to do with the data.

<FAQ>
  <FAQItem
    q="Can I detect the tech stack of a website for free?"
    a="Yes. Free lookup tools and browser extensions both cover single-domain checks. They break down when you need to check hundreds of sites."
  />
  <FAQItem
    q="How accurate is tech stack detection?"
    a="For popular stacks (WordPress, Shopify, React, Cloudflare, etc.) accuracy is 90%+. For obscure or server-side-only tools, it drops quickly."
  />
  <FAQItem
    q="Can I detect the backend language of a website?"
    a="Sometimes. Signals like Set-Cookie headers, error pages, and framework-specific URLs reveal PHP, Ruby, Node, or .NET. Compiled binaries behind a reverse proxy often hide completely."
  />
  <FAQItem
    q="Is it legal to detect a website's tech stack?"
    a="Yes. The data you're analyzing (HTTP responses, HTML, headers) is publicly served by the site. You're reading what the server chose to send you."
  />
  <FAQItem
    q="What's the fastest way to get a list of all sites using a specific technology?"
    a="Buy a dataset. Crawling 3M domains yourself costs weeks of engineering; a pre-filtered CSV costs $29–$499."
  />
</FAQ>

<CTA placement="bottom" target="lookup" />