Load testing tool for developers
Visit WebsiteReviews onG2SourceForge
98 reviews trackedThe Bottom Line
Entry price
Free plan available, paid tiers above
Biggest pro
Developer-friendly load testing
Biggest con
Learning curve
TL;DR - k6
- k6 is an open-source load testing tool for testing API and website performance
- It uses JavaScript to script performance tests with developer-friendly workflows
- Free and open-source, Cloud plans from $99/month
Pricing: Free plan available
Best for: Growing teams
4.5/5 across review platforms
What is k6?
k6 tests performance with modern developer experience. Write tests in JavaScript, run them locally or in cloud-load testing that feels like coding.
The test syntax is clean. The results are detailed. The cloud option scales.
Developers wanting approachable load testing choose k6 for performance testing that fits their workflow.
Available on: Web, Linux, macOS, Windows
LCLouis CorneloupSourcek6.io ↗
Pros & Cons
Pros
- Developer-friendly load testing
- JavaScript scripts
- Good CLI
- Open source
- Grafana integration
Cons
- Learning curve
- Cloud expensive
- Browser testing limited
- Documentation could improve
- Less GUI than alternatives
Ratings Across the Web
4.5(98 reviews)
Ratings aggregated from independent review platforms. Learn more
Key Features
Load testingJavaScriptDeveloper-friendlyCLICloud optionGrafana
Pricing Plans
Free TrialOpen Source
Free
Self-hosted
- Unlimited VUs locally
- Full feature set
- CLI tool
- JavaScript scripting
Most Popular
Grafana Cloud Free
Free
Cloud hosted
- 500 VUh/month
- 14-day retention
- Basic reporting
- Up to 50 concurrent VUs
Pro
$0.15/per VUh
Plus base plan
- 30-day retention
- Advanced reporting
- 8×5 support
- Higher limits
Enterprise
$25,000/year minimum
Volume pricing
- Volume discounts
- Custom SLA
- Dedicated support
- Custom retention
Reviews
4.5/5
Across 98 verified user reviews on SourceForge, G2
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k6 FAQ
Is k6 free?
k6 OSS is free and open source. Grafana Cloud k6 has free tier. Pro and Enterprise for more features.
What is k6?
k6 is a modern load testing tool. Write tests in JavaScript, run from CLI. Acquired by Grafana Labs.
k6 vs JMeter?
k6 is modern, scriptable, and developer-friendly. JMeter is older with GUI. k6 for developers; JMeter for QA teams.
What can you test with k6?
Load testing, stress testing, and API testing. HTTP, WebSocket, and gRPC. Browser testing with k6 browser.
Source: k6.io