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Testing · head to head

k6 vs mabl

k6 logo

k6

Testing

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

From
Free
Rated
-
Full reviewWebsite
mabl logo

mabl

Testing

Low-code browser and API test automation with hosted runners and self-healing selectors

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.; mabl tests are stored in a proprietary format and cannot be exported as runnable code, so migrating to Playwright or Cypress later means re authoring every test by hand.
  • They diverge on capability: k6 covers JavaScript test scripts, mabl covers Trainer recorder.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which k6 and mabl actually diverge.

Attributes where k6 and mabl differ
Attributek6mabl
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsWindows, macOS, Linux, Docker, KubernetesWeb, macOS, Windows, Linux

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 mabl

  • Trainer recorder
  • Auto healing selectors
  • API testing
  • Accessibility checks
  • Cross browser cloud runs
  • CI and issue tracker hooks

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 mabl
  • Generating tens of thousands of requests per second from a small number of machines without a load generator fleetnot mabl
  • Testing gRPC and WebSocket services with the same tooling and thresholds used for HTTP endpointsnot mabl
  • Correlating a load test against existing dashboards for an organisation already running Grafana and Prometheusnot mabl

mabl

  • A QA team of two or three people responsible for regression coverage across a web application released weeklynot k6
  • An organisation that abandoned a Selenium suite because maintenance consumed more time than manual testing didnot k6
  • Teams that need accessibility scanning and functional regression reported in the same runnot k6
  • Product companies where non engineers, such as support or business analysts, are expected to author testsnot 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.

mabl

  • Tests are stored in a proprietary format and cannot be exported as runnable code, so migrating to Playwright or Cypress later means re authoring every test by hand.
  • Auto healing can mask a genuine defect: if an element is removed and a similar one takes its place, the test adapts and passes when a user facing regression has actually shipped.
  • Pricing is not published and is driven by concurrent run capacity, so the cost of shortening a two hour suite to twenty minutes is a renegotiation rather than a configuration change.
  • Debugging a failure happens inside a hosted runner you do not control, which makes flakiness caused by test data or environment timing harder to reproduce locally than with a suite you run yourself.
  • Native mobile application coverage is thin compared with the browser product, so teams with an iOS or Android app still need a second tool such as Appium or Maestro.

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

mabl

On request
  • mabl$undefined/year
    • Annual subscription quoted per organisation, with the number of concurrent cloud runs as the main cost driver
    • Trial available without a sales call, full pricing is not published

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 mabl if

  • You need trainer recorder.
  • You work on Web, macOS, Windows, Linux.
  • You also want auto healing selectors.
mabl review

Questions people ask

Is k6 or mabl better?
Neither clearly leads. k6 starts at Free and mabl at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, k6 or mabl?
k6 has a free tier; the other does not. Paid plans start at Free for k6 and On request for mabl.
Does k6 or mabl run on more platforms?
k6 runs on Windows, macOS, Linux, Docker, Kubernetes. mabl runs on Web, macOS, Windows, Linux.
Can I use k6 for free?
Yes. k6 has a free tier, so you can try it without paying. mabl 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 mabl is typically brought in for.
What can k6 do that mabl cannot?
k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module. mabl covers Trainer recorder, Auto healing selectors, API testing, Accessibility checks.

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.

mabl: Can I export mabl tests to Playwright if we leave?

No. You can export documentation of the steps, but not runnable code. Budget for re authoring the suite.

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.

mabl: Does auto healing actually work?

It works often enough to be the reason people buy it, but it cannot be verified from a demo. Trial it against your own application through at least two real releases.

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.

mabl: Is mabl a replacement for unit tests?

No. It covers end to end journeys through a running application. Unit and integration coverage still belongs in your repository.

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.

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