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Performance Engineering

Measure, find the bottleneck, fix the right thing.

latencythroughputp50p95p99profilingcachingcompressionI/O

Lessons

  1. 13.1Performance vs scalabilityFast for one person is not the same as fast for a million. Learn to tell the two apart, because the fixes are completely different. 30 min Performance vs scalability Scale journey
  2. 13.2Latency percentiles and the tailThe average speed of your site describes nobody. Here's how to see what your unluckiest users actually live with. 30 min Latency percentiles
  3. 13.3Profiling: measure before you optimiseBefore you speed anything up, find out where the time really goes. Your first guess is often wrong. 30 min Incident: checkout is slow Server under load
  4. 13.4Caching strategiesA cache can make a page 40 times faster. It can also show guests a room that's already sold. Here's how to get the first without the second. 30 min Cache strategies
  5. 13.5Latency budgets and the critical path"Make it fast" isn't a plan. A latency budget turns it into a number for each step, so you know exactly where to look. 30 min Latency budget

On the job: try it on your own project

Ask Claude Code to pull latency data from your logs or monitoring and produce a list of your 3 slowest endpoints with p50, p95 and p99. For the worst one, have it profile or trace where the time goes: database, external call, or code. Write a latency budget for that endpoint and one proposed fix, with how you will measure success.

Can you do this now?

0/4. Anything you can't tick yet: reopen that lesson's practice ladder.