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Testing · head to head

k6 vs Split

k6 logo

k6

Testing

Load testing tool with JavaScript tests on a Go runtime, now owned by Grafana Labs

From
Free
Rated
-
Full reviewWebsite
Split logo

Split

Testing

Feature flags tied to a metrics pipeline that attributes production impact to each release, now Harness FME

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only k6 has a free tier, so it costs nothing to try first.
  • Each has a real cost: k6 tests run on a JavaScript engine embedded in Go rather than on Node.js, so npm packages, Node built-ins and existing shared test utilities generally do not work without being bundled to plain JavaScript, and often not even then.; Split split is now a module of the Harness platform and split.io redirects to harness.io, so buying it means entering a Harness commercial relationship rather than a standalone flag vendor contract.
  • They diverge on capability: k6 covers JavaScript test scripts, Split covers Feature flags with targeting.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which k6 and Split actually diverge.

Attributes where k6 and Split differ
Attributek6Split
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsWindows, macOS, Linux, Docker, KubernetesWeb, API, iOS, Android, Java, Node.js, Python, Go, .NET

Identical on both: user rating (Not yet rated), category (Testing).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in k6

  • JavaScript test scripts
  • Thresholds and checks
  • Protocol coverage
  • Browser module
  • Executors
  • xk6 extensions
  • Metrics output
  • Kubernetes operator

Only in Split

  • Feature flags with targeting
  • Metrics impact engine
  • Guardrail metrics
  • Statistical significance testing
  • Event ingestion
  • SDKs and streaming updates
  • Audit and approvals
  • Harness platform integration

What people use each for

The jobs each tool is most often brought in to do.

k6

  • Gating a deployment pipeline on a threshold such as 95th percentile latency under a defined arrival ratenot Split
  • Generating tens of thousands of requests per second from a small number of machines without a load generator fleetnot Split
  • Testing gRPC and WebSocket services with the same tooling and thresholds used for HTTP endpointsnot Split
  • Correlating a load test against existing dashboards for an organisation already running Grafana and Prometheusnot Split

Split

  • A product organisation that wants every release measured against conversion and latency by default, not only deliberate experimentsnot k6
  • Running A/B tests with real statistical significance rather than comparing two dashboard linesnot k6
  • Catching a regression at five per cent rollout because a guardrail metric fires before the change reaches everyonenot k6
  • A team already committed to Harness for CI and CD that wants flags in the same platform and contractnot k6

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

k6

  • Tests run on a JavaScript engine embedded in Go rather than on Node.js, so npm packages, Node built-ins and existing shared test utilities generally do not work without being bundled to plain JavaScript, and often not even then.
  • The open source binary runs on a single machine, so distributed load requires the Kubernetes operator or the cloud service, and the operator is infrastructure your team has to run and debug.
  • The AGPL-3.0 licence on the core requires legal review at any company that intends to embed k6 in a product it distributes or offers as a service, which is a slower path than a permissively licensed tool.
  • There is no result storage in the open source tool, so trend history means standing up Prometheus, InfluxDB or Grafana Cloud before load testing produces anything comparable over time.
  • Since the Grafana Labs acquisition the roadmap serves the Grafana observability stack, so a buyer choosing k6 as a standalone tool should expect the standalone experience to receive less investment than the cloud and dashboard integration.
  • Grafana Cloud billing is by virtual user hour, so a long soak test at modest concurrency costs far more than its peak load suggests, and cost planning has to be done in virtual user hours rather than in test runs.

Split

  • Split is now a module of the Harness platform and split.io redirects to harness.io, so buying it means entering a Harness commercial relationship rather than a standalone flag vendor contract.
  • Harness no longer publishes per-module prices, so an organisation that wants only feature management cannot get a list price and must negotiate a module out of a platform bundle.
  • The measurement engine needs traffic volume to reach significance, so a product with modest usage gets flags with an experimentation layer it will rarely be able to conclude anything from.
  • Metric attribution depends on correctly instrumented events flowing into Split, which is an integration project in its own right; without it you have paid for an experimentation platform and are using it as a flag switch.
  • As part of a larger DevOps suite the roadmap now competes with CI, CD, security and cloud cost modules for attention, so feature management is no longer the company’s single focus the way it was as an independent product.

Pricing, plan by plan

k6

Free
  • k6 OSSFree
    • AGPL-3.0 licence
    • Full test engine, no virtual user limits
    • Runs on one machine unless distributed yourself
  • Grafana Cloud free tierFree
    • Includes a monthly allowance of virtual user hours
    • Hosted test results and dashboards
    • Shared with the rest of the Grafana Cloud free tier
  • Grafana Cloud k6$undefined/month
    • Billed by virtual user hours consumed
    • Load generation from multiple regions
    • Retained test history and comparison

Split

On request
  • Harness FreeFree
    • Harness Open Source and community support
    • Intended for individuals and small teams
    • Feature management capability limited at this tier
  • Harness Essentials$undefined/year
    • Bundled DevOps modules including CI, CD, IaC and security testing
    • Standard support
    • Pricing requires contacting sales
  • Harness Enterprise$undefined/year
    • Mix and match from 15 or more modules including Feature Management and Experimentation
    • Premier support with a dedicated account manager
    • Higher pipeline concurrency and organisation limits

Which should you pick?

Choose k6 if

  • You need javascript test scripts.
  • You want to start without paying.
  • You work on Windows, macOS, Linux, Docker, Kubernetes.
  • You also want thresholds and checks.
k6 review

Choose Split if

  • You need feature flags with targeting.
  • You work on Web, API, iOS, Android, Java, Node.js, Python, Go, .NET.
  • You also want metrics impact engine.
Split review

Questions people ask

Is k6 or Split better?
Neither clearly leads. k6 starts at Free and Split at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, k6 or Split?
k6 has a free tier; the other does not. Paid plans start at Free for k6 and On request for Split.
Does k6 or Split run on more platforms?
k6 runs on Windows, macOS, Linux, Docker, Kubernetes. Split runs on Web, API, iOS, Android, Java, Node.js, Python, Go, .NET.
Can I use k6 for free?
Yes. k6 has a free tier, so you can try it without paying. Split starts at On request.
What is k6 best used for?
k6 is most often used for gating a deployment pipeline on a threshold such as 95th percentile latency under a defined arrival rate, generating tens of thousands of requests per second from a small number of machines without a load generator fleet, testing grpc and websocket services with the same tooling and thresholds used for http endpoints, correlating a load test against existing dashboards for an organisation already running grafana and prometheus. Of those, gating a deployment pipeline on a threshold such as 95th percentile latency under a defined arrival rate and generating tens of thousands of requests per second from a small number of machines without a load generator fleet are not what Split is typically brought in for.
What can k6 do that Split cannot?
k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module. Split covers Feature flags with targeting, Metrics impact engine, Guardrail metrics, Statistical significance testing.

Answered from the vendors’ own pages

k6: Can I use npm packages in a k6 test?

Usually not. Scripts run on a Go-embedded JavaScript engine with no Node.js runtime, so packages depending on Node built-ins fail and pure JavaScript libraries must be bundled first.

Split: Is Split still called Split?

It is now sold as Harness Feature Management and Experimentation after the Harness acquisition, and split.io redirects to harness.io.

k6: Is k6 free?

The core tool is free under AGPL-3.0 with no virtual user limits. Grafana Cloud k6 is a paid service billed by virtual user hours, with a free monthly allowance.

Split: Can I buy just feature flags?

Not from a price list. Harness publishes bundle tiers and directs single-module buyers to sales.

k6: Does the Grafana acquisition affect the open source tool?

The tool remains open source and maintained, but investment is directed at making it a data source for Grafana, so standalone use is supported rather than prioritised.

Split: What does it do that a plain flag service does not?

It attributes changes in your product metrics to specific flags with statistical significance testing and alerts on guardrail metrics.

k6: Can k6 replace a browser testing tool?

No. The browser module measures page-level metrics under load, but functional browser testing belongs in Playwright or a similar tool.

Split: Do we need a lot of traffic?

Yes. Statistical tests need volume to conclude, so low-traffic products get limited value from the measurement layer.

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