Softwr

Testing · head to head

k6 vs Tilt

k6 logo

k6

Testing

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

From
Free
Rated
-
Full reviewWebsite
Tilt logo

Tilt

Developer Tools

Local Kubernetes development loop that rebuilds and live-updates containers on save

From
Free
Rated
-
Full reviewWebsite

The short version

  • 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.; Tilt docker acquired Tilt in 2022 and the team now splits its time across Compose and Docker Desktop, so feature velocity is modest and the product's long-term priority inside Docker is not guaranteed; treat it as a stable utility, not a growing platform.
  • They diverge on capability: k6 covers JavaScript test scripts, Tilt covers Live update.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which k6 and Tilt actually diverge.

Attributes where k6 and Tilt differ
Attributek6Tilt
PlatformsWindows, macOS, Linux, Docker, KubernetesLinux, macOS, Windows
CategoryTestingDeveloper Tools

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

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 Tilt

  • Live update
  • Tiltfile as code
  • Unified web UI
  • Selective rebuilds
  • Local and remote clusters
  • Resource dependencies
  • Extensions registry
  • Custom buttons and triggers

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

Tilt

  • A team of ten or more engineers whose application is fifteen microservices on Kubernetes and who currently wait on CI to test a changenot k6
  • An organisation onboarding new developers who want a single command that stands up the whole stack from a committed Tiltfilenot k6
  • A platform team giving product engineers a consistent local environment against a shared remote development clusternot k6
  • A codebase where one repository contains several services and rebuilding all of them on every edit is the main source of lost timenot 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.

Tilt

  • Docker acquired Tilt in 2022 and the team now splits its time across Compose and Docker Desktop, so feature velocity is modest and the product's long-term priority inside Docker is not guaranteed; treat it as a stable utility, not a growing platform.
  • The Tiltfile is Starlark, a Python dialect, so non-trivial setups become real programs that need reviewing and maintaining, and the person who wrote yours becomes a single point of failure.
  • Live update only works when the running container can accept synced files and restart the process; compiled languages, distroless images and read-only filesystems often force you back to a full image rebuild, which removes the main benefit.
  • It assumes Kubernetes. If your development target is plain Docker Compose or serverless functions, Tilt adds a cluster you did not need and a layer of abstraction with no payoff.
  • There is no commercial support contract, no SLA and no paid tier, so when a Kubernetes version upgrade breaks something you are dependent on GitHub issues and a Slack channel rather than a vendor you can escalate to.

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

Tilt

Free
  • TiltFree
    • Apache 2.0 licensed
    • All features, no paid tier
    • Community support via the Kubernetes Slack #tilt channel

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 Tilt if

  • You need live update.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want tiltfile as code.
Tilt review

Questions people ask

Is k6 or Tilt better?
Neither clearly leads. k6 starts at Free and Tilt at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, k6 or Tilt?
k6 starts at Free and Tilt at Free.
Does k6 or Tilt run on more platforms?
k6 runs on Windows, macOS, Linux, Docker, Kubernetes. Tilt runs on Linux, macOS, Windows.
Can I use k6 for free?
Both have a free tier, so you can try either at no cost before committing.
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 Tilt is typically brought in for.
What can k6 do that Tilt cannot?
k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module. Tilt covers Live update, Tiltfile as code, Unified web UI, Selective rebuilds.

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.

Tilt: Is Tilt free?

Yes, entirely. It is Apache 2.0 open source with no paid tier and no licence fee.

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.

Tilt: Who owns Tilt now?

Docker, which acquired it in May 2022. It remains open source and the repository is still actively maintained.

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.

Tilt: Do I need a remote cluster?

No. It works against a local cluster such as kind, minikube or Docker Desktop, and also against a shared remote development cluster if your services are too heavy to run locally.

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.

Tilt: How is it different from Skaffold?

Both automate the build-deploy loop. Tilt puts more weight on the live-update path and a multi-service dashboard; Skaffold is more configuration-driven and closer to Google's tooling.

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