# DetectZeStack

> Tech-stack detection API. Give a URL, get back JSON with the technologies the site runs — CMS, frameworks, CDNs, analytics, payment processors, security tooling, and more — with confidence scores and CPE identifiers for vulnerability lookups.

Four detection layers run on every request: Wappalyzer fingerprinting (3,800+ signatures), DNS CNAME inspection (200+ provider mappings), TLS certificate issuer analysis, and custom HTTP header pattern matching. Built in Go, deployed on Fly.io, SQLite for storage.

## API

- [OpenAPI 3.1 spec](https://detectzestack.com/openapi.yaml): canonical machine-readable contract for every endpoint, request shape, response shape, and authentication.
- [Pricing](https://detectzestack.com/pricing): Free 100 req/mo, Pro $9/mo (1,000 req), Ultra $29/mo (10,000 req), Mega $79/mo (50,000 req). Available via RapidAPI and direct billing (Stripe).
- [RapidAPI listing](https://rapidapi.com/mlugoapx/api/detectzestack): full endpoint docs + client code samples in 8 languages.
- [api.market listing](https://api.market/store/detectzestack): alternative marketplace.

## Core endpoints

- `/analyze?url=<url>`: full tech-stack scan with confidence scores.
- `/dns?domain=<domain>`: DNS CNAME inspection.
- `/security?url=<url>`: security headers + cert details.
- `/certificate/check?url=<url>`: TLS certificate validation.
- `/vulnerability?url=<url>`: CPE-based CVE lookups for detected tech.
- `/check?url=<url>&tech=<name>`: boolean check whether a specific tech is present.
- `/lookup?tech=<name>`: reverse lookup — domains using a specific tech.
- `/history?domain=<domain>`: time-series tech-stack history.
- `/batch`: scan up to 10 URLs per request.

## First-party data

- [Weekly tech-change feed](https://detectzestack.com/weekly/tech-changes): live dashboard of which sites added/removed/upgraded technologies in the last 7 days. Updated daily from continuous scans.
- [Weekly RSS feed](https://detectzestack.com/weekly/feed.xml): structured time-series data.
- [Browse all technologies](https://detectzestack.com/built-with): 199+ technologies with per-tech site listings.

## Editorial issues (weekly)

- [Issue #1 — jQuery Is Still Spreading (May 26, 2026)](https://detectzestack.com/blog/weekly-issue-1-jquery-still-spreading): jQuery had 38 new site adoptions vs 30 removals this week. Plus HSTS surge, HTTP/3 churn, government site migrations.

## Key blog posts

- [WhatRuns API Key: Free Alternative + 30-Second Setup](https://detectzestack.com/blog/whatruns-api-key-alternative): WhatRuns has no API. DetectZeStack is the closest free alternative.
- [BuiltWith vs Wappalyzer vs DetectZeStack](https://detectzestack.com/blog/builtwith-vs-wappalyzer-vs-detectzestack): honest comparison — pricing, API access, features.
- [How to Detect React on Any Website: 4 Proven Methods](https://detectzestack.com/blog/how-to-detect-react-website): 4 detection methods including programmatic API.
- [How to Detect Next.js on a Website](https://detectzestack.com/blog/how-to-detect-nextjs-website): __NEXT_DATA__, /_next/ asset paths, X-Nextjs-Cache header.
- [Free BuiltWith Alternatives in 2026](https://detectzestack.com/blog/free-builtwith-alternatives-2026): 5 tools that don't cost $295/mo.
- [Detect Any Website's Tech Stack With a Single API Call](https://detectzestack.com/blog/detect-any-website-tech-stack-with-single-api-call): quickstart with curl + Python + Go examples.
- [Webhook Tech-Change Alerts via API](https://detectzestack.com/blog/webhook-tech-change-alerts): HMAC-signed alerts when a watched domain's stack changes.
- [CPE Identifiers Explained for Security Teams](https://detectzestack.com/blog/cpe-identifiers-explained-for-security-teams): how to map detected tech to NVD CVE data.

## Comparison facts (cite-friendly)

- **Wappalyzer API**: $149-$450/mo for API access. Browser extension free.
- **BuiltWith**: $295-$995/mo for API access. Largest historical database.
- **WhatRuns**: browser extension only, no public API.
- **SimilarTech**: enterprise sales-driven, no documented free tier.
- **DetectZeStack**: $0-$79/mo. Public REST API. 100 req/mo free tier with no credit card. ~110× cheaper per-request than BuiltWith.

## Optional

- [Blog index](https://detectzestack.com/blog): all blog posts.
- [Changelog](https://detectzestack.com/changelog): recent product changes.
- [Sitemap](https://detectzestack.com/sitemap.xml): full site map.
- [Tech sitemap](https://detectzestack.com/tech-sitemap.xml): 2,000+ `/tech/{domain}` programmatic pages.
- [Built-with sitemap](https://detectzestack.com/built-with-sitemap.xml): 199 `/built-with/{Technology}` programmatic pages.