Dev

API Latency Napkin

Rough per-request latency and worker busy-fraction estimate.

Free online api latency napkin — runs entirely in your browser. Nothing is sent to our servers.

Capacity napkin math for API design conversations — not a load test. For production SLOs, engage Myrafy.

RTT (ms)

Network hops

Serialize / app (ms)

DB (ms)

Downstream (ms)

Target RPS

Estimate

Network40.0 ms

Server work60.0 ms

Per request100.0 ms

Worker busy fraction5.00

May need concurrency / caching (napkin)

About this tool

Use this free browser-based api latency napkin when you need a quick dev utility without installing software. Processing stays on your device for privacy. Related searches: latency, api, rps, capacity, performance.