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MikeL
MikeL

Posted on • Originally published at detectzestack.com

Build a Website Tech Stack Scanner in Python (Under 50 Lines)

#python #webdev #api #tutorial

Ever wonder what tech stack a website is running? Maybe you're scoping out a competitor, enriching leads, or checking for outdated frameworks with known vulnerabilities.

Here's a Python script that does it in under 50 lines. It calls a tech detection API, parses the response, and gives you a clean report.

The Full Script 

import requests
import sys

API_URL = "https://detectzestack.p.rapidapi.com/analyze"
HEADERS = {
    "X-RapidAPI-Key": "YOUR_API_KEY",
    "X-RapidAPI-Host": "detectzestack.p.rapidapi.com"
}

def scan(url):
    resp = requests.get(API_URL, headers=HEADERS, params={"url": url})
    resp.raise_for_status()
    return resp.json()

def report(data):
    print(f"\n{'=' * 50}")
    print(f"  {data['domain']}  (HTTP {data['status_code']})")
    print(f"  Scanned in {data['detection_time_ms']}ms")
    print(f"{'=' * 50}")

    # Group by category
    by_cat = {}
    for tech in data["technologies"]:
        cat = tech["category"]
        by_cat.setdefault(cat, []).append(tech)

    for cat, techs in sorted(by_cat.items()):
        print(f"\n  {cat}:")
        for t in techs:
            ver = f" v{t['version']}" if t.get("version") else ""
            src = f"[{t['source']}]"
            cpe = f"\n      CPE: {t['cpe']}" if t.get("cpe") else ""
            print(f"    - {t['name']}{ver} {src}{cpe}")

    print(f"\n  Total: {len(data['technologies'])} technologies detected")

if __name__ == "__main__":
    urls = sys.argv[1:] or ["stripe.com"]
    for url in urls:
        report(scan(url))
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Save this as scan.py and run it:

python scan.py stripe.com github.com shopify.com
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Sample Output

Here's what you get for stripe.com:

==================================================
  stripe.com  (HTTP 200)
  Scanned in 847ms
==================================================

  CDN:
    - Cloudflare [dns]

  JavaScript frameworks:
    - React [wappalyzer]

  Web servers:
    - Nginx v1.25.3 [wappalyzer]
      CPE: cpe:2.3:a:f5:nginx:1.25.3:*:*:*:*:*:*:*

  Analytics:
    - Google Analytics [wappalyzer]

  SSL/TLS certificate authorities:
    - Let's Encrypt [tls]

  Total: 5 technologies detected
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What's Happening Under the Hood

The API uses four detection layers:

1. HTTP Header Fingerprinting
Headers like Server: nginx/1.25.3 and X-Powered-By: Express reveal the web server and framework. Fast, but many production sites strip these.

2. HTML/DOM Pattern Matching
The API scans page source for known patterns: <meta name="generator" content="WordPress">, script URLs containing react.production.min.js, CSS class patterns like Tailwind's utilities. This is the core engine — over 7,200 technology signatures via wappalyzergo.

3. DNS CNAME Analysis
A DNS lookup reveals infrastructure that HTTP can't see. example.com CNAME d1234.cloudfront.net → Amazon CloudFront. The API checks against 111 CDN/hosting provider signatures.

4. TLS Certificate Inspection
The certificate authority correlates with infrastructure: Let's Encrypt → self-hosted, Cloudflare Inc → Cloudflare proxy, Amazon → AWS.

Each technology in the response includes a source field (wappalyzer, dns, tls, or headers) so you know exactly how it was detected.

Extending It: Batch Analysis

Need to scan multiple URLs efficiently? The API has a batch endpoint:

import requests

urls = ["stripe.com", "shopify.com", "github.com",
        "notion.so", "vercel.com"]

resp = requests.post(
    "https://detectzestack.p.rapidapi.com/batch",
    headers={
        "X-RapidAPI-Key": "YOUR_API_KEY",
        "X-RapidAPI-Host": "detectzestack.p.rapidapi.com",
        "Content-Type": "application/json"
    },
    json={"urls": urls}
)

for result in resp.json()["results"]:
    techs = [t["name"] for t in result["technologies"]]
    print(f"{result['domain']}: {', '.join(techs)}")
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This sends one HTTP request instead of five.

Extending It: Security Scanning with CPE

The cpe field in the response maps detected technologies to the NVD (National Vulnerability Database). You can cross-reference it to check for known CVEs:

for tech in data["technologies"]:
    if tech.get("cpe"):
        print(f"  {tech['name']} → {tech['cpe']}")
        # Query NVD: https://services.nvd.nist.gov/rest/json/cves/2.0?cpeName={cpe}
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This is useful for security audits and compliance checks.

Getting an API Key

The API is on RapidAPI. The free tier gives you 100 requests/month — no credit card required. Enough to build and test with.

Paid plans start at $9/month for 1,000 requests if you need more volume.

What are you building with tech detection? Competitive analysis dashboards? Lead enrichment pipelines? Security scanners? Drop a comment — I'd love to hear your use case.

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