TEARDOWN 140 · REVIEWED 2026-08-21
Wappalyzer
Wappalyzer identifies the technologies a website runs — CMS, analytics, ecommerce, hosting, JavaScript frameworks — via a browser extension, API, and website. It has grown from a technology-detection tool into a sales-intelligence platform that also sells searchable lead lists of sites using a given technology.
Checking one site's tech stack is replicable for free using an actively maintained open-source fork of Wappalyzer's old signature database, but the paid product's real value — a fresh, searchable list of every site using a given technology — requires an ongoing web-scale crawl that only Wappalyzer runs.
What you lose building it yourself
- ✕A pre-crawled index of which sites use which technology — you'd crawl your own target list from scratch instead
- ✕Website change alerts (needs an ongoing recrawl schedule)
- ✕Bundled email verification and CRM enrichment on the same record
Why people still pay
Worth paying for once you need it across many sites at once — a fresh, searchable index of which companies use a given technology, kept current without running your own crawl.
BUILD YOUR OWN · PARTIAL (LOOKUP ONLY, NOT LEAD LISTS)
A single-site lookup is realistic — an actively maintained open-source fork of Wappalyzer's old signature database still exists to match against. Building the paid product's actual feature, a fresh, searchable list of every site using a given technology, means running that detector across a large, regularly re-crawled slice of the web yourself.
StackNode.js + node-fetch + the enthec/webappanalyzer signature set (JSON pattern definitions) — for the single-lookup version only, no crawler or database needed
Build a Node.js CLI tool that takes a single URL as input and identifies the technologies it uses. Use the open-source technology signature definitions from the enthec/webappanalyzer GitHub repository (JSON files describing patterns to match against HTTP response headers, HTML markup, cookies, script sources, and global JS variables). Fetch the target page's HTML and headers with node-fetch, load the relevant signature JSON files, and run pattern matching against categories like CMS, analytics, ecommerce, and JS framework. Print matched technologies grouped by category to the console.
Similar tools
Free alternative: enthec/webappanalyzer (community fork) — a GPL-3.0, actively maintained continuation of Wappalyzer's original open-source signature database — covers single-site technology detection for free, but comes with no crawled index, no lead lists, and no hosted lookup API.
QUESTIONS
Is the free browser extension still open source?
No — Wappalyzer's original open-source repository is no longer publicly maintained by the company, and the free extension now runs on the same account and lookup-quota system as the paid plans. An independent community fork keeps the old signature database going.
Does Wappalyzer only detect SEO-relevant technology?
No — it detects the full stack (CMS, analytics, payment, hosting, JS frameworks, and more). SEO or competitive research is only one of several use cases the product is now built around, alongside sales lead generation.
Can I still use Wappalyzer just to check one competitor's site?
Yes, within the free tier's 50-lookups-a-month cap — beyond that, or to build lists across many sites at once, a paid plan is required.