Apache JMeter vs Grafana k6

Free and open source

From $19 per month (indicative, Grafana Cloud k6 entry)

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

Self-hosted is free and unlimited. Cloud plans are billed by virtual-user-hours, which is where budgets go.

Everything, self-hosted

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

Category standard

Apache Software Foundation · since 1998

Category standard

Grafana Labs · since 2016

• 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.

• 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.

• 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.

• 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.

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

Engineering teams that want performance regression tests running in CI.