ComposalVisual testing
Composal vs Lost Pixel
Lost Pixel asks whether a captured UI differs from its baseline and offers a visual-test workflow.
Two workflows, side by side
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 →Lost Pixel
Open-source and hosted visual regression testing
Lost Pixel provides visual regression testing for Storybook, Ladle, and web applications, with an open-source runner and a hosted platform. Teams capture screenshots, compare them against baselines, and review changes through their development workflow.
What each tool does
“With setup” means you supply code or configuration. “Not confirmed” means support for this workflow needs checking with the vendor.
| Workflow | Composal | Lost Pixel |
|---|---|---|
| Run browser journeys | Yes Run saved browser Scenarios and return recordings and reproducible Findings. | With setup Captures or compares rendered pages through a configured test or visual workflow; confirm the supported runner. |
| Map application workflows | 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 | 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 | 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 | Yes Use the CLI to start and inspect verification runs and their Findings. | Not confirmed Check whether this product includes this workflow in your intended plan and setup. |
| Visual regression baselines | No Use a dedicated tool for this specialist workflow alongside Composal’s browser verification. | Yes Lost Pixel provides visual regression testing for Storybook, Ladle, and web applications, with an open-source runner and a hosted platform. Teams capture screenshots, compare them against baselines, and review changes through their development workflow. |
Where each fits
Choose Lost Pixel when screenshot comparison, Storybook coverage, or an open-source visual-testing foundation fits your frontend process.
Try this evaluation
Select two states: a component documented in Storybook and an application journey that submits it in context. Make one styling change and one interaction change.
- 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?