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testcritic

Grafana k6 vs Apache JMeter vs Gatling

Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.

Entry price

From $19 per month (Grafana Cloud Pro platform fee; k6 usage is billed on top)

Free tier

Free and open source

Open source

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

Free tier

What drives the bill

The metric that actually scales your invoice.

Self-hosted is free and unlimited. On Grafana Cloud the free tier includes 500 virtual-user-hours a month, then k6 bills from $0.150 per virtual-user-hour on top of the $19 Pro platform fee — the VU-hours, not the platform fee, are where budgets go.

Free. Costs are load-generator infrastructure and, commonly, a cloud execution service such as BlazeMeter.

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

Free tier

The k6 CLI is fully open source with no virtual-user limits when self-run.

Everything, self-hosted

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

Open source

AGPL-3.0

Apache-2.0

Apache-2.0

Self-hostable

No-code authoring

Languages

JavaScriptTypeScript
JavaCodeless
JavaKotlinJavaScriptTypeScript

Platforms

APIWeb
APIWeb
APIWeb

Fits teams

Solo / side projectStartupScale-up / mid-marketEnterprise
Scale-up / mid-marketEnterprise
StartupScale-up / mid-marketEnterprise

Adoption

Category standard

Grafana Labs · since 2016

Category standard

Apache Software Foundation · since 1998

Widely used

Gatling Corp · since 2012

Strengths

  • Excellent resource efficiency — thousands of virtual users from one modest machine.
  • Thresholds make performance a build gate rather than a report nobody reads.
  • Native Grafana and Prometheus integration ties load results to server-side metrics.
  • Protocol coverage no modern tool matches — JDBC, JMS, LDAP, mainframe-adjacent protocols.
  • GUI test-plan building is accessible to testers who do not code.
  • Enormous body of documentation, plugins and available expertise.
  • 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.

Limitations

  • The JavaScript runtime is not Node — no npm modules unless bundled, which surprises people.
  • Browser-level load testing exists but is much heavier and less mature than protocol-level testing.
  • Distributed execution requires either the cloud product or your own orchestration.
  • Thread-per-user model is memory-hungry; high load needs a cluster where k6 needs one box.
  • JMX test plans are XML that merges terribly in version control.
  • The GUI must not be used for actual load generation, which trips up nearly every beginner.
  • 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.

Best for

Engineering teams that want performance regression tests running in CI.

Enterprise performance teams needing protocol breadth and a GUI-based workflow.

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

All of these integrate with: Grafana, Jenkins.

Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.