Percy vs Chromatic

Thinking of visual testing using Chromatic or one of the other Percy competitors? It can be time-consuming to scan each feature of every tool, so we gathered some handy info that’ll make it easier to decide which visual testing tool is right for you.

Read on for an overview of Chromatic and Percy, including features, workflows, and pricing. We hope this helps you figure out the best testing solution for your project.

Jump to section

• Can you set up Percy by yourself?
• Is Percy visual testing flaky?
• Is Percy fast?
• How does Percy handle branching and merging for baselines?
• How do you debug tests in Percy?
• How do you collaborate in Percy?
• What browsers does Percy support?
• What does Percy cost vs Chromatic?
• Is Percy free?
• How does Chromatic visual testing integrate with my tech stack?
• Chromatic is perfect for Storybook
• Ready to try Chromatic?

Can you set up Percy by yourself?

Yes, you’ll need a Browserstack account to start using Percy.

Chromatic is designed for developers to get started in 90 seconds. Best-practice defaults come out of the box to prevent misconfiguration. In as little as three lines of code, you’ll be up and running.

Is Percy visual testing flaky?

It depends. Percy visual tests are only as reliable as the code being tested. Your visual tests may be flaky if your UI renders inconsistently. For example, with randomized data, flashes of un-styled content, or slow loading resources.

Visual testing tools mitigate flake in a number of ways. With Chromatic, we prevent flake using a standardized browser environment that auto-detects UI loading, painting, and reflowing to determine the most reliable time to snapshot. We believe this prevents flake before it can affect your tests. Chromatic has run over 7.3 billion tests across thousands of companies.

Is Percy fast?

The faster your tests run, the faster you iterate. When comparing visual testing tools, parallelization is the key differentiator for speed. Running tests in sequence can be up to 30 minutes slower than running tests in parallel.

Percy charges you extra for parallel test runs. You get “X parallels” for most plans. “X” is not a typo, it’s the actual unit of measure Percy uses. How many concurrent processes “X” amounts to is unclear.

Chromatic runs your tests with unlimited parallelization, all your tests run simultaneously. The infrastructure is effectively able to run your entire test suite simultaneously and optimizes for fastest test times. Every plan comes with fastest possible test speeds.

To give a benchmark for speed, Chromatic can take a snapshot and diff 2000 tests in less than 2 minutes. If you’re using Chromatic’s TurboSnap, you can further speed up your tests by 85% for the same coverage.

How does Percy handle branching and merging for baselines?

A baseline represents what a test is supposed to look like. How a visual testing tool manages baselines is important to consider because you may have to change the way you work in order to use the tool.

Percy has a basic baseline algorithm. It compares changes on a feature-branch to a main branch. But you end up running into baseline issues when doing common branch-based development like merging a second branch into your feature branch (e.g., telescoping PRs) or updating your branch from main.

Chromatic tracks baselines using Git. It mirrors how developers track code changes. Your baselines persist through branches and merges without you having to change the way you work. This allows entire engineering organizations to work on features together without merge conflicts from your visual tests.

How do you debug tests in Percy?

“But it works on my machine.” If you build UIs for a living like us, you've probably heard this countless times. The differences in UI rendering between environments is a common source of frustration for developers. What you want from a visual testing tool is a standardized environment and the ability to debug in your own browser.

Percy doesn’t allow you to inspect the rendered code under test. You have to run your test suite again locally to reproduce errors. This increases the time it takes to debug issues.

Chromatic prioritizes reproducibility. It doesn’t just capture an image snapshot, it archives the DOM, styling, and assets at the specific point in time of a test. You can inspect the code behind every change in your own browser via the Chromatic web app. This allows developers to debug exactly what your users and teammates would see.

How do you collaborate in Percy?

Percy has unlimited users but doesn’t allow you to assign reviewers or track who reviewed what. Chromatic has unlimited users by default with no per seat cost. It syncs permissions automatically, includes customizable roles, and commenting.

Chromatic was built for collaboration from the start. Product teams can review UI changes together in one place. Every review is associated with a user so you can see who approved what and when. Engineers, designers, and product managers can browse the test library online without needing to pull code, migrate, or maintain a dev environment.

What browsers does Percy support?

Percy supports a variety of browsers, but this can be a double-edged sword. The more browsers you enable, the slower your tests, the higher the maintenance effort, and the higher the costs.

Chromatic supports the latest stable versions of the world's most common browsers, which cover 95.93% of users. To ensure the best performance, Chromatic also runs all browsers with unlimited parallelization.

Why? Browser rendering engines used to be quite different. Each browser implemented CSS differently, which meant developers had to check that the UI rendered right in every browser.

Modern browsers interpret CSS and JavaScript similarly and update themselves automatically. This negates the value of having browser farms with myriad versions. Testing with the latest stable version of the most popular browsers gives you high coverage at a pragmatic price.

What does Percy cost vs Chromatic?

Percy’s starter plan is $249/mo when billed monthly. That amounts to $12,000 a year more than Chromatic for equivalent snapshot usage¹.

Chromatic also provides unlimited parallelization for much faster tests, no-hassle branching, painless merging, and intuitive collaboration.

What’s more, TurboSnap can provide up to 85% faster test runs and on average 41% cost savings for the same coverage. It works by tracking code to test only what's changed. Percy doesn’t have any feature that delivers this level of value.

¹ Calculated using Percy's monthly cost plus the difference in additional snapshots.

² Chromatic is optimized for speed. Your tests run on as many machines as needed to get you results in the least time by default.

Is Percy free?

Percy has a free plan with a 5000 snapshot limit and a limit on parallelization. Chromatic has a free plan with 5000 snapshots and unlimited parallelization.

How does Chromatic visual testing integrate with my tech stack?

Adding visual testing to the software development lifecycle requires integrations with existing developer tools, git providers, and collaboration tools. In a nutshell, below are the most important integrations to consider.

Chromatic integrates with all of the above. Our integrations are as native as possible. We map 1-to-1 concepts like Storybook stories and Playwright tests with visual tests. For example, every story is transformed into a visual test automatically. And every Playwright test for a user flow gets visually tested in its end state (and optionally along the way). All of this reduces test maintenance for you.

Chromatic is perfect for Storybook

We maintain Storybook, the industry-standard open source tool for frontend developers. With Chromatic, we created a way to automatically visual test everything you develop in Storybook.

Chromatic tests map 1-to-1 with your stories. Whenever you update a story your tests are synced. This means visual tests are painless to keep up to date. Storybook's own visual tests feature is powered by Chromatic.

Ready to try Chromatic?

Finding the right visual testing tool can be hard. We hope this guide makes it a bit clearer. Trying Chromatic is easy, setup your project in less than 90 seconds. No credit card required.