FastAPI Security 100 LVL: Production-Grade DDoS Protection

Your FastAPI is going down under load — and you're reading the slowapi docs thinking that'll be enough? Spoiler: it won't. About as effective as a bike lock against a professional thief. Let's break it all down — layer by layer — the way senior security engineers do it in production. No fluff, real code, some humor, and a clear understanding of why each decision is made the way it is — not just "I saw someone do it this way once." 📋 Version note. This article went through a security review — 5 real production bugs were found and fixed: limit_request_size middleware removed (bypassable via Transfer-Encoding: chunked), asyncio.wait_for wrapper around the ASGI app removed (DB connection leak on cancellation), Sliding Window Log on ZSET replaced with Sliding Window Counter via HINCRBY (O(1) vs O(N)), CircuitBreaker moved from process memory to Redis (worker isolation), AnomalyDetector rid of defaultdict in memory (leak + event loop blocking). Details in each section. Why FastAPI Is Especi