capacity-estimation

Capacity estimation with numbers computed in code, not in prose. It starts from measured metrics when the system exists, or from order-of-magnitude scenarios and decision thresholds when there are no metrics (exploratory design, PoC), leaning on the business archetype. Covers QPS, storage, bandwidth, Little's law, utilization and queues, fan-out and tail latency, composed availability, shards, backlog and burn rate. Use it when a decision depends on scale ("will it hold?", "how many instances?", "do we need to shard?", "capacity planning", "back-of-the-envelope").

License

MIT