# Composal vs Biome

Biome checks source patterns and formatting in supported files. Composal evaluates the deployed application through browser Scenarios and exploration, which complements rather than replaces linting.

## 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)

## Biome

JavaScript, CSS, and JSON linting and formatting

Biome provides a linter with rule-based static diagnostics and an integrated formatter. Its documentation covers recommended and configurable rules, safe fixes, editor integration, and supported language areas.

## What each tool does

| Workflow | Composal | Biome |
| --- | --- | --- |
| [Run browser journeys](https://composal.com/product/scenarios) | ✓ Yes: Run saved browser Scenarios and return recordings and reproducible Findings. | × No: The documented product reviews or analyzes source changes; it does not execute browser journeys. |
| [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. | – Not confirmed: Check whether this product includes this workflow in your intended plan and setup. |
| [Run or inspect from a terminal](https://composal.com/product/cli) | ✓ Yes: Use the CLI to start and inspect verification runs and their Findings. | – With setup: Connect its specialist checks to your development workflow using supported integrations. |
| Source code review and analysis | × No: Use a dedicated tool for this specialist workflow alongside Composal’s browser verification. | ✓ Yes: Biome provides a linter with rule-based static diagnostics and an integrated formatter. Its documentation covers recommended and configurable rules, safe fixes, editor integration, and supported language areas. |

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

## Where each fits

Choose Biome when a unified tool for supported language linting and formatting fits your repository. Choose Composal for web acceptance checks, recordings, and Findings tied to actual application behavior.

## Try this evaluation

Run Biome on changed frontend files and use Composal on a preview of the same feature. Compare fixable source diagnostics with browser results for a success path and an error path.

### 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 GitHub CodeQL](https://composal.com/compare/composal-vs-codeql.md)
- [Composal vs OWASP ZAP](https://composal.com/compare/composal-vs-owasp-zap.md)
- [Composal vs Burp Suite](https://composal.com/compare/composal-vs-burp-suite.md)

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