Show HN: I built a zero-log PII redaction API – no AI, just regex and checksums

Hi HN,

I built PII Firewall because I got tired of watching "privacy" APIs secretly pipe user data to cloud AI models. If you're using GPT/Claude to redact PII, you're literally giving the AI your PII.

What makes this different:

- Zero AI – deterministic regex + 30 checksum validators (Luhn, Verhoeff, Mod 11/97) - Zero storage – processes on Cloudflare edge, no logs, no persistence - 152 PII types – SSN, Aadhaar, 50+ country IDs, 20 API key formats, crypto wallets - Two modes: `/fast` (2-5ms) for structured PII, `/deep` (5-15ms) adds names/addresses via 2000+ name gazetteer

The technical approach:

Instead of ML inference, I use combined V8-optimized regex with heuristic pre-scanning. Clean text (90% of requests) skips pattern matching entirely. For IDs that require it, I implemented full checksum validation:

- Credit cards: Luhn - Indian Aadhaar: Verhoeff - Chinese ID: ISO 7064 Mod 11 - Brazilian CPF/CNPJ: Dual Mod 11 - IBAN: Mod 97

Runs on Cloudflare Workers (pure JS, no WASM), so no cold starts.

Why I'm sharing:

Enterprise PII solutions cost $50K+/year. I wanted to make this accessible to indie devs, startups, and anyone building AI features who doesn't want to become a data liability. The $5/mo tier covers most use cases.

Would love feedback on the detection coverage or edge cases I might be missing.