# Composal vs Grafana k6

k6 measures system performance under load and can assert response correctness and thresholds. Composal checks user-facing web outcomes in browser runs; it is not a load generator or a performance-testing replacement.

## Composal

Composal sends AI browser agents to use your running web app and check the outcomes you care about. Define journeys as plain-English Scenarios, map existing flows with Discovery, or explore for bugs with Deep Scan. Runs keep recordings and reproduction steps so your team or coding agent can investigate a Finding.

[Verify documentation](https://composal.com/docs/verify)

## Grafana k6

Scriptable load and performance testing

Grafana k6 is an open-source load-testing tool with JavaScript or TypeScript test scripts and local or cloud execution options.

## What each tool does

| Workflow | Composal | Grafana k6 |
| --- | --- | --- |
| [Run browser journeys](https://composal.com/product/scenarios) | ✓ Yes: Run saved browser Scenarios and return recordings and reproducible Findings. | ✓ Yes: The k6 browser module executes browser journeys and collects frontend performance metrics. |
| [Map application workflows](https://composal.com/product/discovery) | ✓ Yes: Discovery maps key application areas and user journeys. | – Not confirmed: Check whether this product includes this workflow in your intended plan and setup. |
| [Explore for unexpected issues](https://composal.com/product/deep-scan) | ✓ Yes: Deep Scan explores the running application and reports reproducible issues. | – Not confirmed: Check whether this product includes this workflow in your intended plan and setup. |
| [Describe checks in plain English](https://composal.com/product/scenarios) | ✓ Yes: Author Scenarios around the intended user outcome, then review the steps and expected results. | – With setup: Author browser interactions and assertions in JavaScript or TypeScript. |
| [Run or inspect from a terminal](https://composal.com/product/cli) | ✓ Yes: Use the CLI to start and inspect verification runs and their Findings. | ✓ Yes: Execute scripts with the k6 command-line runner. |
| Performance measurement and load testing | × No: Use a dedicated tool for this specialist workflow alongside Composal’s browser verification. | ✓ Yes: Grafana k6 is an open-source load-testing tool with JavaScript or TypeScript test scripts and local or cloud execution options. |

With setup means you supply code or configuration. Not confirmed means support for this workflow needs checking with the vendor.

## Where each fits

Choose k6 when the team needs repeatable, scriptable load tests and performance thresholds for APIs or services. Choose Composal when you need an independent browser QA pass over a preview, saved journey, or exploratory workflow.

## Try this evaluation

Use a representative API-backed journey.

### Coverage

Which user outcomes must this release prove, and which specialist checks must stay in your existing stack?

### Setup

Who prepares accounts, test data, permissions and access to the deployment being tested?

### Evidence

Can the engineer reproduce a reported failure from the recording and steps, without asking the tester to investigate again?

### Ownership

Who updates the checks when the product changes, and can the team review what a passing result actually proves?

## Related comparisons

- [Composal vs Apache JMeter](https://composal.com/compare/composal-vs-apache-jmeter.md)
- [Composal vs Gatling](https://composal.com/compare/composal-vs-gatling.md)
- [Composal vs Lighthouse](https://composal.com/compare/composal-vs-lighthouse.md)

[All comparisons](https://composal.com/compare.md)