HyperLogLog: Count Distinct at Scale in 12KB
Counting unique items exactly costs memory that grows with your data. HyperLogLog estimates the cardinality of billions in about 12KB. Here's how it works.
#Redis(3)
Rate Limiting a FastAPI Service with a Token Bucket
Add per-user rate limiting to a FastAPI backend with the token bucket algorithm: an in-process version, an atomic Redis script, 429s, and the failure modes.
FastAPI BackgroundTasks vs a Task Queue
FastAPI BackgroundTasks run inside your web process and disappear on restart. When that is fine, when you need a real task queue, and how to move over.