Experiments

If you'd like to try out what we're working on in Cypress, you can enable beta features for your project by turning on the experimental features you'd like to try.

⚠️ The experimental features might change or ultimately be removed without making it into the core product. Our primary goal for experiments is to collect real-world feedback during their development.

Configuration

You can pass the Cypress configuration options below to enable or disable experiments. See our Configuration Guide on how to pass configuration to Cypress.

Option	Default	Description
`experimentalFetchPolyfill`	`false`	Automatically replaces `window.fetch` with a polyfill that Cypress can spy on and stub. Note: `experimentalFetchPolyfill` has been deprecated in Cypress 6.0.0 and will be removed in a future release. Consider using cy.intercept() to intercept `fetch` requests instead.
`experimentalInteractiveRunEvents`	`false`	Allows listening to the `before:run`, `after:run`, `before:spec`, and `after:spec` events in the setupNodeEvents function during interactive mode.
`experimentalModifyObstructiveThirdPartyCode`	`false`	Whether Cypress will search for and replace obstructive code in third party `.js` or `.html` files. NOTE: Setting this flag removes Subresource Integrity (SRI).
`experimentalSourceRewriting`	`false`	Enables AST-based JS/HTML rewriting. This may fix issues caused by the existing regex-based JS/HTML replacement algorithm. See #5273 for details.
`experimentalWebKitSupport`	`false`	Enable experimental support for running tests in WebKit. When set, installs of `playwright-webkit` will be detected and available in Cypress. See Launching Browsers for more information.

Testing Type-Specific Experiments

You can provide configuration options for either E2E or Component Testing by creating e2e and component objects inside your Cypress configuration.

End-to-End Testing

These experiments are available to be specified inside the e2e configuration object:

Option	Default	Description
`experimentalSessionAndOrigin`	`false`	Enables cross-origin and improved session support, by adding the `cy.origin()` and `cy.session()` commands. This also enables the concept of Test Isolation, which is `on` by default.
`experimentalStudio`	`false`	Generate and save commands directly to your test suite by interacting with your app as an end user would.

Component Testing

These experiments are available to be specified inside the component configuration object:

Option	Default	Description
`experimentalSingleTabRunMode`	`false`	Run all specs in a single tab, instead of creating a new tab per spec. This can improve run mode performance, but can impact spec isolation and reliability on large test suites.

History

Version	Changes
10.8.0	Added `experimentalWebKitSupport`.
10.6.0	Added support for `experimentalSingleTabRunMode`.
10.4.0	Added support for `experimentalModifyObstructiveThirdPartyCode`.
9.6.0	Added support for `experimentalSessionAndOrigin` and removed `experimentalSessionSupport`.
8.2.0	Added support for `experimentalSessionSupport`.
7.1.0	Added support for `experimentalInteractiveRunEvents`.
7.0.0	Removed `experimentalComponentTesting` and made it the default behavior.
6.7.0	Removed `experimentalRunEvents` and made it the default behavior.
6.3.0	Added support for `experimentalStudio`.
6.2.0	Added support for `experimentalRunEvents`.
6.0.0	Removed `experimentalNetworkStubbing` and made it the default behavior when using cy.intercept().
6.0.0	Deprecated `experimentalFetchPolyfill`.
5.2.0	Removed `experimentalShadowDomSupport` and made it the default behavior.
5.1.0	Added support for `experimentalNetworkStubbing`.
5.0.0	Removed `experimentalGetCookiesSameSite` and made it the default behavior.
4.9.0	Added support for `experimentalFetchPolyfill`.
4.8.0	Added support for `experimentalShadowDomSupport`.
4.6.0	Added support for `experimentalSourceRewriting`.
4.5.0	Added support for `experimentalComponentTesting`.
4.3.0	Added support for `experimentalGetCookiesSameSite`.