# Composal vs GitLab Duo Code Review

Duo reviews merge requests in GitLab. Composal checks deployed browser journeys and records what users see when expectations fail.

## 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)

## GitLab Duo Code Review

AI-assisted merge request review in GitLab

GitLab offers non-agentic Duo Code Review and agentic Review Flow. Availability depends on the add-on and instance settings.

## What each tool does

| Workflow | Composal | GitLab Duo Code Review |
| --- | --- | --- |
| [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: GitLab offers non-agentic Duo Code Review and agentic Review Flow. Availability depends on the add-on and instance settings. |

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

## Where each fits

Choose Duo when your team already manages merge requests and AI review policy in GitLab. Choose Composal for hosted browser Scenarios, Discovery, Deep Scan, and Findings that can be handed to a coding agent.

## Try this evaluation

Use a merge request changing account permissions. Compare review comments with Composal runs for both allowed and denied browser paths; record which issues require a live app and which are visible from code context.

### 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 Amazon Q Developer code review](https://composal.com/compare/composal-vs-amazon-q-developer.md)
- [Composal vs CodeScene](https://composal.com/compare/composal-vs-codescene.md)
- [Composal vs Review Board](https://composal.com/compare/composal-vs-review-board.md)

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