We ran the website tech stack detector on 12 addresses: 11 real sites and one made-up domain to see how a failure is reported. The failed one came back as fetch_failed: ENOTFOUND instead of as an empty result, so a dead domain does not look like a site with no technology.
86 detections across 11 sites, 39 distinct technologies. A site returns between 5 and 10 (median 8).
Most common technologies: HSTS (11), Open Graph (10), Content Security Policy (6), Cloudflare (5), RSS (4), Web App Manifest (4). Most common categories (sites per category): Security (11), Metadata (10), Hosting (5), CDN (5), Analytics (4), CMS (4).
The top entries are security headers and metadata (HSTS, Open Graph), not products. That is what a header-and-HTML detector sees first; products that leave no trace in headers or markup are not found. Server headers: cloudflare (5), nginx (1), Vercel (1), Heroku (1), github.com (1).
76 of 86 detections carry a confidence below 100, so the confidence field is worth filtering on if you need precision.
Input: 12 results from a test run of the website-tech-stack-detector actor, stored as techstack.json with evidence strings removed. The figures on this page are computed by a4_techstack.py (run it from the articles/_data folder). Related: the actor page and its sample CSV. Published 2026-10-13. We build and maintain these actors.