The best open source alternative to BuiltWith is Blacklight Privacy Inspector. If that doesn't suit you, our users have ranked more than 25 alternatives to BuiltWith and four of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to BuiltWith are HTTP Observatory, Ingredients and Web Metadata & Contact Extractor.
Who is peeking over your shoulder while you work, watch videos, learn, explore, and shop on the internet? Enter the address of any website, and Blacklight will scan it and reveal the specific user-tracking technologies on the site—and who’s getting your data.
United States
Developed by Mozilla, the HTTP Observatory performs an in-depth assessment of a site’s HTTP headers and other key security configurations.
United States
Ingredients is a website scanner that is able to determine the "ingredients" (or technologies) behind a website.
Web Metadata & Contact Extractor is a REST API that takes any URL and returns SEO/OpenGraph metadata, contact info (emails + social links), detected tech stack, security headers, Schema.org JSON-LD, and a clean Markdown version of the page content -- all in a single call.
Spain
EU