Inspiration
Kept losing scraping sessions to silent fingerprint mismatches. The proxy IP was clean but DNS was leaking to a different ASN, or the browser fingerprint was flagged as unique enough to track across sessions. Needed a quick way to verify everything before running against production targets.
What it does
A set of browser privacy and proxy testing tools that check the signals anti-bot systems actually look at:
- IP type detection (mobile, residential, datacenter) with ASN and carrier info
- DNS resolver consistency check (does the DNS ASN match the connection IP ASN)
- WebRTC leak detection (checks if the real IP leaks through WebRTC even behind a proxy)
- Browser fingerprint uniqueness scoring (canvas, WebGL, fonts, screen, timezone)
- Platform detection simulation (what Instagram, TikTok, and Facebook would flag about the current setup)
How I built it
Frontend runs client-side JavaScript fingerprinting checks. Backend handles IP lookups, ASN classification, and DNS resolver identification through server-side queries. Playwright used for testing and validating detection accuracy against known anti-bot systems.
Challenges
Getting accurate carrier classification for mobile IPs was harder than expected. Many IP databases misclassify carrier-grade NAT ranges. Had to cross-reference multiple data sources to get reliable mobile vs residential vs datacenter classification.
Accomplishments that I'm proud of
The platform detection simulator turned out more useful than expected. It shows exactly what specific platforms (Instagram, Facebook, TikTok) would flag about a given setup, not just generic fingerprint data. Developers testing multi-account configurations use it to catch problems before burning live accounts.
What I learned
DNS resolver ASN mismatch is probably the most underrated detection signal. Most developers check their proxy IP and stop there. The DNS resolver tells a completely different story and platforms absolutely check it.
What's next for Proxy Fingerprint Validator
Adding a proxy speed and latency benchmarking tool that measures response time across different geographic endpoints. Also working on a carrier DNS consistency checker that automates the ASN comparison between connection IP and DNS resolver instead of requiring manual cross-referencing
