Performance Debugging Methodology
Performance work should follow measurement rather than intuition. Start by identifying the slow user journey, measure network and rendering timings, locate the bottleneck, change one variable, and measure again.
Common bottleneck categories include server response time, database latency, external APIs, JavaScript execution, image delivery, font loading, and client-side rendering.
A useful performance review should produce numbers rather than vague statements such as 'the page feels slow.'
Key Takeaways
- Measure before optimizing.
- Separate server, network, browser, and database bottlenecks.
- Verify that an optimization actually improves the target metric.