Performance Testing
Performance Testing
Testing how the system behaves under various load conditions — speed, stability, scalability.
Full definition
Performance testing evaluates how a system performs under various conditions, focusing on responsiveness, throughput, reliability, and scalability.
Types of performance testing:
- Load testing: Expected user load — does the system handle normal traffic?
- Stress testing: Beyond normal capacity — where does the system break?
- Spike testing: Sudden traffic bursts — how does the system handle spikes?
- Endurance/Soak testing: Sustained load over time — are there memory leaks?
- Scalability testing: Increasing load — does the system scale linearly?
Key metrics:
- Response time: How fast pages/APIs respond
- Throughput: Requests per second the system handles
- Error rate: Percentage of failed requests under load
- Concurrent users: How many simultaneous users are supported
Popular tools: JMeter, Gatling, k6, Locust, Artillery
Performance testing should happen early and often, not just before release. Performance budgets and automated performance tests in CI/CD prevent regression.