What should I use for load testing APIs?

For load testing APIs, the best tool depends on what you want to test and how much scripting you need. Good options:

Popular choices

• k6 — Great modern choice for API load testing.

  • Easy to script in JavaScript
  • Good for CI/CD and automation
  • Strong metrics and reporting
  • Best if you want developer-friendly load tests

• JMeter — Classic, very widely used.

  • Good for complex scenarios
  • Huge ecosystem and plugins
  • Can be heavier and more cumbersome than k6
  • Best if your team already knows it or needs advanced protocol support

• Locust — Python-based load testing.

  • Easy if your team uses Python
  • Flexible for custom behavior
  • Good for simulating user flows
  • Best for code-heavy, behavior-driven tests

• Gatling — Strong performance and detailed reports.

  • Scala-based
  • Excellent for high-load testing
  • Very good reporting
  • Best if you’re comfortable with its language and want polished results

Quick recommendation

• Simple REST/GraphQL API testing: k6
• Python-friendly workflows: Locust
• Enterprise/legacy/very complex testing: JMeter
• High-scale and detailed performance analysis: Gatling

If you want a simple starting point

Use k6 unless you have a specific reason not to. It’s lightweight, modern, and easy to integrate into CI.

If you want, I can also give you:

1. a comparison table of these tools, or
2. a minimal k6 script to start load testing an API.