Softwr

Testing · head to head

k6 vs Umami

k6 logo

k6

Testing

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

From
Free
Rated
-
Full reviewWebsite
Umami logo

Umami

Marketing

Open source, cookie-free web analytics you can self-host for the cost of a database

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.; Umami there is no cohort analysis, retention curve, session replay or multi-touch attribution, so a marketing team that needs to justify channel spend will still buy a second tool and Umami becomes a supplementary dashboard.
  • They diverge on capability: k6 covers JavaScript test scripts, Umami covers Cookie-free tracking.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which k6 and Umami actually diverge.

Attributes where k6 and Umami differ
Attributek6Umami
Pricing modelOpen source, no licence feePer month by event count
PlatformsWindows, macOS, Linux, Docker, KubernetesWeb, Linux
CategoryTestingMarketing

Identical on both: starting price (Free), 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 Umami

  • Cookie-free tracking
  • Self-hosting
  • Small tracking script
  • Custom events
  • Funnels and goals
  • Multi-site and teams
  • Public dashboards
  • API access

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

Umami

  • A developer who wants traffic numbers on a personal or client site without adding a consent bannernot k6
  • An organisation whose legal or procurement team has ruled out sending visitor data to a US advertising companynot k6
  • A high-traffic site where hosted analytics priced by pageview band has become expensive and self-hosting removes the ceiling entirelynot k6
  • A team that wants analytics data in a database they already control so they can query and join it themselvesnot 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.

Umami

  • There is no cohort analysis, retention curve, session replay or multi-touch attribution, so a marketing team that needs to justify channel spend will still buy a second tool and Umami becomes a supplementary dashboard.
  • Self-hosting is only free in licence terms; you own the database, the upgrades, the backups and the query performance at scale, and a busy site's events table grows quickly enough to need real attention.
  • Because it stores no persistent identifier, it cannot follow a user across devices or sessions in any meaningful way, which makes returning-visitor and lifetime-value questions unanswerable by design rather than by omission.
  • Cloud overage is billed per event beyond the plan allowance, so a traffic spike or a badly instrumented custom event can produce a bill materially above the $20 or $200 headline before anyone notices.
  • It is maintained by a small team, so the pace of new capability is modest and enterprise expectations such as SSO, granular role permissions and formal support agreements are limited compared with commercial analytics vendors.

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

Umami

Free
  • Self-hostedFree
    • MIT licensed, no licence fee
    • No event limit imposed by the software
    • Unlimited websites and users
  • Cloud HobbyFree
    • Up to 100,000 events per month
    • 3 websites
    • 6 months data retention
  • Cloud Pro$20/month
    • Up to 1,000,000 events per month
    • Unlimited websites
    • Unlimited team members
  • Cloud Business$200/month
    • Up to 10,000,000 events per month
    • All Pro features
    • Higher volume overage rate

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 Umami if

  • You need cookie-free tracking.
  • You want to start without paying.
  • You work on Web, Linux.
  • You also want self-hosting.
Umami review

Questions people ask

Is k6 or Umami better?
Neither clearly leads. k6 starts at Free and Umami at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, k6 or Umami?
k6 starts at Free and Umami at Free.
Does k6 or Umami run on more platforms?
k6 runs on Windows, macOS, Linux, Docker, Kubernetes. Umami runs on Web, Linux.
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 Umami is typically brought in for.
What can k6 do that Umami cannot?
k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module. Umami covers Cookie-free tracking, Self-hosting, Small tracking script, Custom events.

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.

Umami: Is Umami really free?

Self-hosted, yes; it is MIT licensed with no event cap. You pay for the server and database. Umami Cloud has a free tier at 100,000 events a month and paid tiers from $20.

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.

Umami: Do I need a cookie consent banner?

For Umami analytics specifically, generally no, because it sets no cookies and stores no personal data. Other tags on your site may still require one.

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.

Umami: Can it replace Google Analytics?

For traffic, referrers and event counts, yes. For attribution modelling, audiences and advertising integration, no.

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.

Umami: What does it need to run?

A container and a PostgreSQL or MySQL database. Most people deploy it on infrastructure they already pay for.

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