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Testing · head to head

k6 vs Spring Cloud Gateway

k6 logo

k6

Testing

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

From
Free
Rated
-
Full reviewWebsite
Spring Cloud Gateway logo

Spring Cloud Gateway

APIs

API gateway built on Project Reactor for building microservices

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.; Spring Cloud Gateway released under the Apache 2.0 license, free and open source with no commercial tier
  • They diverge on capability: k6 covers JavaScript test scripts, Spring Cloud Gateway covers Routing.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which k6 and Spring Cloud Gateway actually diverge.

Attributes where k6 and Spring Cloud Gateway differ
Attributek6Spring Cloud Gateway
Pricing modelOpen source, no licence feeopen-source
PlatformsWindows, macOS, Linux, Docker, KubernetesJava, Spring Boot
CategoryTestingAPIs
FoundedUnknown1998

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 Spring Cloud Gateway

  • Routing
  • Path Rewriting
  • Circuit Breaker
  • Spring Boot
  • Spring Security
  • Spring Cloud
  • Java support
  • Spring Boot support

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

Spring Cloud Gateway

  • API Developmentnot k6
  • API Gatewaynot k6
  • API Testingnot k6
  • API Documentationnot k6
  • Microservicesnot 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.

Spring Cloud Gateway

  • Released under the Apache 2.0 license, free and open source with no commercial tier

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

Spring Cloud Gateway

Free
  • Open SourceFree
    • Core Spring Cloud Gateway
    • Community support

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 Spring Cloud Gateway if

  • You need routing.
  • You want to start without paying.
  • You work on Java, Spring Boot.
  • You also want path rewriting.
Spring Cloud Gateway review

Questions people ask

Is k6 or Spring Cloud Gateway better?
Neither clearly leads. k6 starts at Free and Spring Cloud Gateway at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, k6 or Spring Cloud Gateway?
k6 starts at Free and Spring Cloud Gateway at Free.
Does k6 or Spring Cloud Gateway run on more platforms?
k6 runs on Windows, macOS, Linux, Docker, Kubernetes. Spring Cloud Gateway runs on Java, Spring Boot.
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 Spring Cloud Gateway is typically brought in for.
What can k6 do that Spring Cloud Gateway cannot?
k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module. Spring Cloud Gateway covers Routing, Path Rewriting, Circuit Breaker, Spring Boot.

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.

Spring Cloud Gateway: Is Spring Cloud Gateway free?

Yes, Spring Cloud Gateway is free and open-source software. It is part of the Spring ecosystem and available through GitHub repositories with open-source dependencies like spring-cloud-starter-gateway-server-webflux and spring-cloud-starter-gateway-server-webmvc.

Source
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.

Spring Cloud Gateway: What enterprise support is available for Spring Cloud Gateway?

Tanzu Spring provides optional enterprise support including Day 0 access to security patches for organizations requiring guaranteed support, but specific pricing is not published on the Spring Cloud Gateway project page.

Source
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.

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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