# Performance Testing Performance testing is the practice of evaluating how a system behaves under various levels of load and stress. It measures key metrics such as response time, throughput, error rate, and resource utilization to determine whether the system meets performance requirements and can handle expected traffic volumes. Types of performance testing include load testing (simulating expected concurrent users), stress testing (pushing beyond normal capacity to find breaking points), spike testing (sudden traffic surges), and endurance testing (sustained load over extended periods). Tools like k6, Apache JMeter, Gatling, and Locust are commonly used to simulate client traffic and measure system behavior. For API systems, performance testing validates that API endpoints respond within acceptable latency thresholds under realistic traffic patterns. Testing should include the full request path through the API gateway to measure the overhead introduced by authentication, rate limiting, and routing logic. In serverless architectures, performance testing also helps identify cold start impacts and concurrency limits that affect real-world response times. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.serverlessapigateway.com/glossary/p/performance-testing.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.