k6
Developer-friendly performance testing in JavaScript. CLI-first, CI-native, and now part of Grafana Labs.
Overview
k6, created by Load Impact in 2016 and acquired by Grafana Labs in 2021, is a modern load testing tool designed for developers. Tests are written in JavaScript (actually a V8-based Go runtime) and executed from the command line. k6 is built for CI/CD: it returns exit codes, outputs machine-readable metrics, and integrates natively with Grafana for visualisation.
In 2026, k6 is the default choice for teams that want code-based performance testing with modern developer experience. It is particularly strong for API load testing and can simulate thousands of concurrent virtual users from a single machine.
What it's used for
k6 is ideal when:
- Developer-centric performance testing: Tests are JavaScript code, version-controlled, and reviewed in PRs.
- API load testing: Simulate thousands of concurrent users hitting REST, GraphQL, or gRPC endpoints.
- CI/CD integration: Run performance tests on every commit with pass/fail thresholds.
- Real-time monitoring: Stream results to Grafana dashboards during test execution.
Pros & Cons
Pros
- JavaScript syntax — familiar to most developers
- Extremely fast execution (Go-based engine)
- Native CI/CD integration with thresholds and exit codes
- Excellent Grafana integration for visualisation
- Free and open source with generous cloud options
Cons
- Browser-level testing requires k6 Browser (separate, less mature)
- No GUI for test creation — everything is code
- JavaScript-only — not suitable for Java or Python teams
- Distributed load testing requires k6 Cloud or custom orchestration
- Less mature for complex web app scenarios than JMeter or NeoLoad
Platforms & Integrations
k6 runs on Windows, macOS, and Linux. It requires no runtime dependencies beyond the k6 binary. Cloud execution is available via k6 Cloud (Grafana).
Pricing
| Tier | Cost | Includes |
|---|---|---|
| Open Source | Free | Unlimited local execution, all core features |
| k6 Cloud | From $59/mo | Cloud execution, distributed load, analytics, 50 VU minimum |
| Enterprise | Custom | Private cloud, dedicated support, custom SLAs |
NZ Context
k6 is rapidly becoming the standard for API performance testing in NZ tech companies. Startups like Figured and Crimson Education use k6 for load testing their APIs. NZ developer job postings increasingly list k6 as a preferred performance testing tool. For NZ teams already using Grafana for monitoring, k6 is a natural extension.
Alternatives
- JMeter — More mature for complex web scenarios. GUI-based test creation.
- Gatling — Scala-based with excellent reporting. Better for high-concurrency scenarios.
- Artillery — JavaScript/JSON-based load testing. Similar developer experience to k6.