---
name: Performance Testing
description: Validate speed and scalability under load.
---
# Performance Testing

Performance testing finds the system's breaking points before users do. "It feels fast in dev" with one user tells you nothing about peak hour.

## Types
- **Load.** Expected peak traffic. Does it meet latency/SLO targets?
- **Stress.** Beyond peak — where does it break, and how? Graceful degradation or crash?
- **Soak / endurance.** Sustained load over hours. Catches memory leaks, resource exhaustion, GC death-spirals.
- **Spike.** Sudden bursts. Can it absorb without cascading failure?

## Method
- **Test the real path.** Representative request mix, real data volume, production-like config. Synthetic loops mislead.
- **Define targets first.** "p95 < 200ms at 1000 RPS" — without targets, results are uninterpretable.
- **Find the bottleneck, then stop.** Identify the limiting resource (CPU, DB, network); fixing it changes everything else.