I ran two jobs so far tonight, the first was just going through and documenting my project, that seemed to go well. After that, I challenged claude to use that document and do a deep dive security analysis of the auth in my app. It identified all of these issues: Session Validation Bypass (CRITICAL) Missing Rate Limiting (HIGH) Weak CSRF Protection (HIGH) Client-Modifiable Attribution Data (MEDIUM-HIGH) Missing Email Verification (MEDIUM) Username Enumeration (MEDIUM) Weak Password Policy (LOW-MEDIUM) Missing Account Lockout Mechanism (HIGH) Missing Rate Limiting on Critical Endpoints (HIGH) Missing HSTS Header (MEDIUM-HIGH) Attribution Cookie Security Weaknesses (MEDIUM) So I went through and addressed these one by one with ChatGPT Codex, and left three outstanding that were just going to add more hassle to dev/testing with a mind to implement them before deployment. Here is the final writeup that claude gave the app: Summary of Final Security Analysis 🎉 Excellent News! Security Grade: A- (Strong) Your authentication system is now production-ready with only the deferred items remaining! ✅ What's Working Exceptionally Well 1. Triple-Layer Session Validation - Defense in depth with middleware, server actions, and route guards 2. Comprehensive Rate Limiting - All critical endpoints protected (auth, checkout, username checks) 3. Account Lockout System - Prevents distributed brute force attacks 4. Strong CSRF Protection - Exact origin matching for all state-changing requests 5. Attribution Cookie Security - HMAC-SHA256 with timing-safe comparison 6. HSTS Header in Production - 2-year HTTPS enforcement 7. Email Verification - Required before login 8. Webhook Security - Stripe signature verification with idempotency 🟢 Critical Vulnerabilities: NONE! All previous critical issues have been resolved. ⚠️ Remaining Items (All Deferred as Planned) HIGH Priority (before production): 1. Weak password policy (intentionally deferred) 2. No MFA yet (intentionally deferred) 3. Insecure cookies in dev (intentionally deferred)