k6

Overview

k6 is an open-source load testing tool from Grafana Labs. Test scripts are ES modules (JavaScript, or TypeScript run directly by k6) that define virtual users (VUs), scenarios and thresholds; k6 run executes them and exits non-zero when a threshold fails. This skill covers writing scripts, choosing a test type, thresholds, custom metrics, running locally, in Docker and in CI. k6 v2 (2026) removed old commands and options; see Guidelines.

Instructions

Initial Assessment

Before writing a load test, understand:

1. Target — What endpoint(s) or service are you testing?
2. Goal — What kind of test? (load, stress, spike, soak, smoke)
3. Expectations — What response time and error rate are acceptable?
4. Scale — How many concurrent users should the test simulate?

Writing k6 Scripts