Load Testing

Find your breaking point before customers do

Most outages happen when traffic spikes and a dependency fails at the same time. Harness tests both conditions simultaneously so you know exactly where your system breaks.

Why Harness

Validate performance and resilience in a single test run

Most load testing tools tell you when your system falls over. Harness tells you whether it recovers automatically when a service fails during peak load.

Combined chaos and load

Load tests tell you if your system handles volume. They do not tell you what breaks when a service fails during that surge.

Harness runs load tests and chaos fault injection simultaneously in a single native workflow, so you test resilience under real conditions.

Safe for production testing

Testing under load in production without controls risks overwhelming live systems or triggering real incidents.

Built-in blast radius controls, rate limiting, and emergency stop let you run load tests safely in production during off-peak hours.

Pipeline-gated releases

Performance regressions ship because there is no automated check on latency and recovery time at deploy time.

Automated SLA pass/fail gates in your Harness pipeline block any release that fails latency, error rate, or recovery time thresholds.

How It Works

Get complete resilience coverage in every test run

Most teams test load and faults in isolation. Harness runs them simultaneously, injecting failures into a live system while it is under traffic pressure.

Define and run load tests

Configure users, duration, ramp-up, and test type natively in the Harness UI.

No external tooling needed
Set a fault injection trigger

Define when chaos fires: at a VU threshold, a time offset, or a pipeline stage.

Precise fault timing
Watch the combined impact

See req/s, error rate, and response time update live as the fault plays out.

Real-time visibility
Gate releases on results

Set pass/fail thresholds on latency and recovery time. Failed runs block the pipeline.

Regressions never ship
Full platform capabilities

Load testing capabilities

Run load tests natively in Harness alongside chaos engineering to validate how your system holds up under real traffic pressure.

Chaos testing

Inject controlled faults to identify system weak points and validate behavior under stress with proactive failure simulation.

Locust and K6 engine

Harness load testing runs natively on Locust and K6. Configure test parameters directly in the Harness UI.

Load test patterns

Ramp, spike, soak, and breakpoint test patterns to match real traffic scenarios. Gradually increase load to find exact breaking points without over-testing.

Performance metrics

Track p50/p95/p99 response times, TPS throughput, and error rates in real time as faults play out against your running load test.

SLA pass/fail gates

Automated SLA pass/fail gates integrated directly into CI/CD pipelines. Set latency and error rate thresholds that block a release when the combined test fails.

Composite tests

Combine API and browser load in a single test execution. Test the full user journey under realistic mixed traffic while chaos experiments run in parallel.

Use cases

Real-world use cases

How teams use Harness load testing to validate performance and resilience before traffic hits production.

Pre-launch capacity validation

Simulate launch day traffic and inject a fault into a critical dependency mid-ramp to find breaking points before go-live.

Peak traffic resilience

Run multi-stage load tests from baseline to 10x peak while injecting faults at each stage to validate graceful degradation.

API performance regression

Catch latency regressions before they reach production using p50/p95/p99 monitoring and automated SLA gates in the deploy pipeline.

Auto-scaling under fault conditions

Drive load to the HPA trigger threshold and inject a node eviction to verify the cluster recovers within SLA during combined load and fault.

FAQ

Frequently asked questions

Yes, when configured correctly. Harness includes built-in blast radius controls, rate limiting, and an emergency stop that halts fault injection immediately without stopping the load test. Start during off-peak hours and increase load gradually once you have validated the blast radius settings.

Harness load testing runs natively on Locust and K6. You configure users, duration, ramp-up duration, and test type directly in the Harness UI. Harness handles execution, real-time monitoring, and pass/fail evaluation.

Harness runs both simultaneously. You define a load test and set a trigger point for fault injection — a VU threshold, a time offset, or a pipeline stage. When the trigger fires, Harness injects the chosen fault while the load test continues running. Results from both are correlated in the Harness dashboard.

Yes. Harness integrates load testing directly into deployment pipelines. Set SLA thresholds on latency, error rate, and recovery time. Harness evaluates the combined load and chaos result automatically and blocks the pipeline if thresholds are not met.

Start with a baseline that matches current production traffic, then test at 2x, 5x, and 10x expected peak. Use ramp, spike, soak, and breakpoint patterns to cover different failure modes. Harness supports all of these natively with configurable ramp-up duration and user counts.

Harness tracks total requests, requests per second, p50/p95/p99 response times, TPS throughput, error rate, and average response time in real time. All metrics are correlated against the running chaos fault timeline so you can see exactly when and how the system degraded.

Get started with Harness Load Testing

Validate performance and resilience together. No credit card required.