Infrastructure Service · Security & Middleware
GuardRail API Gateway
High-performance API proxy with token bucket rate-limiting, internal IP SSRF filtering, and JWT validation.
Overview
A lightweight API gateway designed to protect internal microservices from SSRF vulnerabilities and traffic spikes. What I built - Token bucket rate-limiting middleware backed by Redis atomic memory operations - Strict SSRF network guard rejecting private IP ranges (RFC 1918, RFC 4193) and cloud metadata URLs - Stateless JWT verification and header sanitization for downstream routing - Structured audit logging and metrics export Engineering highlights - Built with Fastify for ultra-low latency request routing - 100% test coverage on security edge cases (DNS rebinding, IPv6 mapped IPv4) - Zero memory leakage under sustained high concurrency
Technology
- Fastify
- Node.js
- TypeScript
- Redis
- NextAuth.js
- Zod
- Docker