k6 vs Artillery: which load testing tool fits your team?

k6 and Artillery are both open source, code-first load testing tools, and either one will load test an HTTP API well. Pick k6 if you want a single binary, test logic in JavaScript and pass/fail thresholds built in. Pick Artillery if your team already lives in Node.js, prefers short YAML scenarios, or wants Playwright browser tests and distributed runs on AWS or Azure from the command line.

The facts below come from each project’s own documentation and repository, checked on 8 October 2026.

What is the difference between k6 and Artillery?

They differ mainly in runtime and in how you describe load. k6 is a compiled Go tool that runs JavaScript test code, while Artillery is a Node.js tool that reads YAML or JavaScript scenarios.

That difference shows up on day one. Installing k6 means one package or a standalone binary, with no language runtime to manage. Artillery needs Node.js and installs through npm, which feels natural in a JavaScript project and is one more runtime to keep current anywhere else.

On protocols the overlap covers most web work: both speak HTTP and WebSockets out of the box. k6 also ships with gRPC, and Artillery with Socket.IO. Artillery gets gRPC and Kinesis from add-on engines that you install separately (checked on 9 October 2026), and k6 reaches further through its extension ecosystem.

How do you write a test in each tool?

In k6 you write a JavaScript module with options at the top and a default function that each virtual user runs. In Artillery you usually write a YAML file with a config block for the load and a scenarios block for what each virtual user does.

A k6 test that ramps to 20 virtual users and fails if the 95th percentile response time goes above 500 ms:

import http from "k6/http";
import { check, sleep } from "k6";

export const options = {
  stages: [
    { duration: "30s", target: 20 },
    { duration: "1m", target: 20 },
    { duration: "15s", target: 0 },
  ],
  thresholds: { http_req_duration: ["p(95)<500"] },
};

export default function () {
  const res = http.get("https://staging.example.com/api/users");
  check(res, { "status is 200": (r) => r.status === 200 });
  sleep(1);
}

The same idea in Artillery’s YAML format, with ten new virtual users arriving every second for a minute:

config:
  target: "https://staging.example.com"
  phases:
    - duration: 60
      arrivalRate: 10
  plugins:
    ensure:
      thresholds:
        - "http.response_time.p95": 500
scenarios:
  - flow:
      - get:
          url: "/api/users"

The two examples model load in different ways. The k6 script sets a number of concurrent virtual users, and the Artillery file sets how many new virtual users arrive each second. k6 can also drive arrival rates through its scenario executors, and Artillery can cap concurrency with maxVusers, so choose the model that matches how real traffic reaches your system rather than the one each tool shows first.

How do k6 and Artillery decide whether a test passed?

Both turn a performance goal into an exit code, which is what a CI pipeline needs. A missed goal ends the run with a non-zero exit code in either tool.

In k6 the goals are thresholds, set in the script’s options as in the example above. In Artillery they live in the ensure plugin, which supports simple thresholds and conditions that combine several metrics.

The practical difference is where the goals sit. k6 thresholds live next to the test logic in the same file. Artillery’s checks live in the config block, where someone who never touches the scenarios can still adjust them.

How do you run a bigger test than one machine can generate?

Both tools can spread a test across many machines, through quite different routes. k6 leans on Kubernetes or Grafana’s hosted service, and Artillery leans on your own AWS or Azure account.

For k6, the k6-operator splits a test across pods in a Kubernetes cluster, and Grafana Cloud k6 runs the same scripts as a hosted service. For Artillery, the run-lambda and run-fargate commands launch workers in your AWS account after a one-time IAM setup through a CloudFormation stack. On Azure, run-aci does the same with Azure Container Instances, though using it beyond evaluation needs a paid Artillery subscription (checked on 9 October 2026). If you already run Kubernetes, the operator route will feel familiar. If you would rather not operate anything, Artillery’s serverless route has fewer moving parts, as long as the test can live in AWS or Azure.

There is a third route for k6 scripts. LoadFocus runs k6 scripts on its own cloud infrastructure from 25 regions, so the script you run on your laptop becomes a distributed test without a cluster or an AWS account. LoadFocus does not run Artillery scripts, so for Artillery its own AWS and Azure commands remain the way to scale.

Where do the results go?

Both tools print a summary at the end of a run and can send metrics to other systems for dashboards and alerting.

k6 offers summary statistics or granular metrics exported to the service of your choice, according to its repository. Artillery lists more than 20 integrations for monitoring, observability and CI/CD in its repository. Either tool can feed the dashboards you already have. Check that the specific output you need is on the list before you commit, because both lists change between releases.

Which one should you choose?

Choose k6 when you want one binary in CI, JavaScript test logic with real control flow, and thresholds in the same file as the test. It also suits teams that already use Grafana, since the open source tool and the hosted service share one scripting API.

Choose Artillery instead when your team writes Node.js every day, when a short YAML file is easier for the rest of the team to review than a script, or when you need Playwright browser tests and Socket.IO in the same tool. Its serverless scaling is also the shorter path if your infrastructure already lives in AWS and Kubernetes is not part of it.

If you are still undecided, write the same smoke test in both. Twenty lines are enough to see which one your team finds easier to read in a code review.

FAQ

Is k6 free to use? Yes. k6 is open source under the AGPL-3.0 licence and runs on your own machines at no cost. Grafana Cloud k6 is a separate hosted service with its own pricing.

Is Artillery free to use? Mostly. Most of Artillery is under the MPL-2.0 licence, while some Azure-specific modules use a source-available licence that requires a commercial licence for production use on Azure, according to the project repository (checked on 8 October 2026).

Can LoadFocus run Artillery tests? No. LoadFocus runs k6 and JMeter scripts. To scale an Artillery test beyond one machine, use Artillery’s own commands for AWS Lambda, Fargate or Azure Container Instances in your own cloud account.

Which tool uses fewer resources on the load generator? We have not measured this ourselves, so we will not name a winner. The k6 project says even lower-end machines can simulate a lot of traffic, and the fair way to compare is to run the same scenario with both tools on your own hardware.

Related reading

• Gatling vs k6: JVM simulations or a single Go binary?
• How to run a load test: a step-by-step guide
• Open source load testing tools: six options reviewed
• Load testing in GitHub Actions: a practical guide
• k6 vs Locust: JavaScript scripts or Python users?
• Artillery load testing: a review of the Node.js tool

The technical claims in this article have not been independently reviewed.