ENGINEERING NOTES

API Performance Testing with Locust and Go

A practical Performance Testing note for QA Engineers: Locust for Python scripts, Go load frameworks behind Locust WebUI for heavier concurrency, and what to measure beyond green charts.

Python Locust suite · Go workers + Locust WebUI

  • Performance Testing
  • Locust
  • Go
  • API Testing

What Performance Testing should prove

Performance Testing is not a vanity QPS number. For API Testing under load, I care about latency distribution, error budget, saturation points, and whether the database or cache is the first wall.

Locust stays in my toolkit because it is Python-native, scriptable, and easy to keep next to API automation practice suites.

Go workers + Locust WebUI

When concurrency needs to climb, I do not stay on Python alone. A Go load framework drives the workers while Locust still owns the master WebUI — same charts, hatch rate, and distributed control, with Go handling the heavy request path.

That split keeps the familiar Locust operator experience, and lets me choose the worker language by pressure and ecosystem — Python for fast scripting, Go when throughput and resource efficiency matter more.

Where the practice lives

My public Python project includes Locust, API, Selenium, and Appium examples. The Go practice repo is where I keep language-side load and tooling experiments that plug into the same Locust WebUI workflow.

Signals I watch

When load rises, I look for:

  • p95 / p99 latency cliffs
  • Error rate vs throughput tradeoffs
  • DB lock / connection pool pressure
  • Cache miss amplification

Contact:

Open for collaboration, consulting, and engineering opportunities.

  • AI Testing tools / ClawHub skill customization
  • QA / SDET consulting and team advisory
  • Test infrastructure / Docker environment enablement
  • Open-source collaboration with InnoNestX