Visual testing

Composal vs BackstopJS

BackstopJS gives teams control over screenshot scenarios and visual baselines. Composal provides hosted browser Scenarios and exploratory QA for checking user outcomes, with Findings organized for follow-up.

See where each fits ↓

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 →

BackstopJS

Open-source visual regression testing

BackstopJS is an open-source visual regression tool that captures web pages and compares them with reference screenshots.

What each tool does

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

Composal and BackstopJS workflow capabilities
Workflow	Composal	BackstopJS
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 BackstopJS is an open-source visual regression tool that captures web pages and compares them with reference screenshots.

Where each fits

Choose BackstopJS when you want an open-source, self-hosted visual regression suite and are comfortable maintaining its fixtures and execution setup.

Try this evaluation

Create a small BackstopJS suite for three stable pages and one responsive viewport pair. In parallel, define a Composal Scenario for the main task that crosses those pages. Introduce one controlled layout shift and one functional defect.

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?