Resource loading
Chromatic waits for resources like images and fonts to load before capturing a snapshot. When resources fail to load, this can lead to unintended UI changes.
Chromatic has a multistage timeout for capturing a snapshot: 15 seconds to render a story and an additional 15 seconds to execute interaction tests, if present. If the resources fail to load in time, Chromatic will retry. After several retries, the snapshot will be captured, and a warning message will be displayed.
Avoid external resources
External resources depend on network stability and third-party hosting, so they may not load predictably. Whenever possible, serve resources alongside the UI you’re testing to make builds faster and more stable.
| Integration | Recommendation |
|---|---|
| Storybook | Serve static files with Storybook. If you can’t include an image locally, use a reliable placeholder service. For more recommendations, see the Storybook image loading guide. |
| Playwright | Serve resources from your local application server. If resources must come from another domain, add the domain to assetDomains in your Chromatic configuration for Playwright. |
| Cypress | Serve resources from your local application server. If resources must come from another domain, add the domain to assetDomains in your Chromatic configuration for Cypress. |
Asynchronous rendering
Our browsers monitor network activity while your tests are rendered. If your test renders after a delay (i.e., asynchronously), we cannot tell what happened. Thus, we can’t reliably wait for subsequent resources to be loaded asynchronously.
If you know how long async rendering takes, you can add a delay to avoid snapshotting until after that happens. However, it can be difficult to reliably set a time that network resources will load within, so you may have to add/subtract seconds to the delay.
We are investigating ways to add first-class support for asynchronous rendering to Storybook and Chromatic. Let us know if you need this feature by chat or email.