I built an API that detects any website's tech stack — free tier, 10x cheaper than BuiltWith

I've been working on DetectZeStack, a REST API that identifies technologies on any website.

The problem: I needed tech stack data for lead enrichment. BuiltWith charges $295/month for API access. Wappalyzer's API starts at $450/month.

My approach: Combine 4 detection methods in one API call:

1. HTTP fingerprinting (wappalyzergo — 3,500+ signatures)
2. DNS CNAME analysis (reveals CDNs, hosting — 29 signatures)
3. TLS certificate inspection (reveals cloud providers — 8 patterns)
4. Custom header matching

Plus: CPE vulnerability identifiers for every detected technology, batch analysis (up to 10 URLs), stack comparison, and webhook alerts.

Try it: https://detectzestack.fly.dev — the demo analyzes any URL, no signup needed.

Browse pre-analyzed sites: https://detectzestack.fly.dev/tech/github.com, https://detectzestack.fly.dev/tech/stripe.com

Free tier: 100 requests/month. Pro: 25,000 for $29.99/month.

Built with Go, SQLite, deployed on Fly.io. Total infra cost: ~$5/month.

What features would make this more useful for you?