Gatling vs Locust

From €89 per month (indicative, Enterprise Cloud entry)

Free and open source

Open source is free; Enterprise adds distributed injectors and reporting, billed by virtual-user-hours.

Free and open source. You pay in engineering time and CI minutes.

Gatling open source is complete for single-machine load generation.

Everything, self-hosted

Widely used

Gatling Corp · since 2012

Widely used

OSS community · since 2011

• Very high throughput per load generator thanks to the async architecture.
• Code-first scenarios that review, diff and refactor properly.
• The default HTML report is genuinely good enough to hand to a stakeholder.

• Test scenarios are plain Python, so any logic is expressible without workarounds.
• Distributed mode is conceptually simple and works well on Kubernetes.
• Live web UI is useful during an exploratory ramp-up.

• Historically Scala-first; the Java and JavaScript DSLs are newer and less documented.
• Fewer protocols than JMeter.
• Distributed load without the enterprise product means building your own orchestration.

• Python's per-user overhead is higher than k6 or Gatling; big loads need more machines.
• Reporting is basic — plan on exporting to Grafana.
• HTTP-centric; other protocols require writing your own client.

JVM teams wanting code-first performance tests with excellent reporting.

Python teams who want load scenarios expressed in their own language.