Vegeta vs Grafana k6

Free and open source

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

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

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.

Established

OSS community · since 2013

Category standard

Grafana Labs · since 2016

• Constant-rate model avoids the coordinated-omission problem that distorts VU-based tools.
• Single static binary, trivial to run anywhere.
• Composable output for scripting and pipelines.

• 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.

• No scenarios or session state — one target list, one rate.
• No GUI or built-in reporting beyond plots.
• Go library usage required for anything sophisticated.

• 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.

Backend engineers who want rigorous constant-rate measurements of an endpoint.

Engineering teams that want performance regression tests running in CI.