Configuration (Legacy)

caution

This guide is for Cypress 9 and below, which supports the cypress.json configuration file. For Cypress 10 and above, visit the Configuration guide.

cypress.json

The first time you open Cypress, it creates the cypress.json configuration file. This JSON file is used to store any configuration values you supply. If you configure your tests to record the results to Cypress Cloud the projectId will be written in this file too.

caution

Change Configuration File

You can change the configuration file or turn off the use of a configuration file by using the --config-file flag.

Options

The default behavior of Cypress can be modified by supplying any of the following configuration options. Below is a list of available options and their default values.

Global

Option	Default	Description
baseUrl	null	URL used as prefix for cy.visit() or cy.request() command's URL
clientCertificates	[]	An optional array of client certificates
env	{}	Any values to be set as environment variables
includeShadowDom	false	Whether to traverse shadow DOM boundaries and include elements within the shadow DOM in the results of query commands (e.g. cy.get())
numTestsKeptInMemory	50	The number of tests for which snapshots and command data are kept in memory. Reduce this number if you are experiencing high memory consumption in your browser during a test run.
port	null	Port used to host Cypress. Normally this is a randomly generated port
redirectionLimit	20	The number of times that the application under test can redirect before erroring.
reporter	spec	The reporter used during cypress run
reporterOptions	null	The reporter options used. Supported options depend on the reporter.
retries	{ "runMode": 0, "openMode": 0 }	The number of times to retry a failing test. Can be configured to apply to cypress run or cypress open separately. See Test Retries for more information.
watchForFileChanges	true	Whether Cypress will watch and restart tests on test file changes

Timeouts

tip

Core Concept

Timeouts are a core concept you should understand well. The default values listed here are meaningful.

Option	Default	Description
defaultCommandTimeout	4000	Time, in milliseconds, to wait until most DOM based commands are considered timed out
execTimeout	60000	Time, in milliseconds, to wait for a system command to finish executing during a cy.exec() command
taskTimeout	60000	Time, in milliseconds, to wait for a task to finish executing during a cy.task() command
pageLoadTimeout	60000	Time, in milliseconds, to wait for page transition events or cy.visit(), cy.go(), cy.reload() commands to fire their page load events. Network requests are limited by the underlying operating system, and may still time out if this value is increased.
requestTimeout	5000	Time, in milliseconds, to wait for a request to go out in a cy.wait() command
responseTimeout	30000	Time, in milliseconds, to wait until a response in a cy.request(), cy.wait(), cy.fixture(), cy.getCookie(), cy.getCookies(), cy.setCookie(), cy.clearCookie(), cy.clearCookies(), and cy.screenshot() commands
slowTestThreshold	10000 | 250	Time, in milliseconds, to consider a test "slow" during cypress run. A slow test will display in orange text in the default reporter. You will often want to configure this differently for component and e2e testing. Default is 10000 for e2e and 250 for component tests.

Folders / Files

Option	Default	Description
downloadsFolder	cypress/downloads	Path to folder where files downloaded during a test are saved
fileServerFolder	root project folder	Path to folder where application files will attempt to be served from
fixturesFolder	cypress/fixtures	Path to folder containing fixture files (Pass false to disable)
ignoreTestFiles	*.hot-update.js	A String or Array of glob patterns used to ignore test files that would otherwise be shown in your list of tests. Cypress uses minimatch with the options: {dot: true, matchBase: true}. We suggest using https://globster.xyz to test what files would match.
integrationFolder	cypress/integration	Path to folder containing integration test files
pluginsFile	cypress/plugins/index.js	Path to plugins file. (Pass false to disable)
screenshotsFolder	cypress/screenshots	Path to folder where screenshots will be saved from cy.screenshot() command or after a test fails during cypress run
supportFile	cypress/support/index.js	Path to file to load before test files load. This file is compiled and bundled. (Pass false to disable)
testFiles	**/*.*	A String or Array of glob patterns of the test files to load
videosFolder	cypress/videos	Path to folder where videos will be saved during cypress run

Screenshots

Option	Default	Description
screenshotOnRunFailure	true	Whether Cypress will take a screenshot when a test fails during cypress run.
screenshotsFolder	cypress/screenshots	Path to folder where screenshots will be saved from cy.screenshot() command or after a test fails during cypress run
trashAssetsBeforeRuns	true	Whether Cypress will trash assets within the downloadsFolder, screenshotsFolder, and videosFolder before tests run with cypress run.

For more options regarding screenshots, view the Cypress.Screenshot API.

Videos

Option	Default	Description
trashAssetsBeforeRuns	true	Whether Cypress will trash assets within the downloadsFolder, screenshotsFolder, and videosFolder before tests run with cypress run.
videoCompression	32	The quality setting for the video compression, in Constant Rate Factor (CRF). The value can be false to disable compression or a value between 0 and 51, where a lower value results in better quality (at the expense of a higher file size).
videosFolder	cypress/videos	Where Cypress will automatically save the video of the test run when tests run with cypress run.
video	true	Whether Cypress will capture a video of the tests run with cypress run.
videoUploadOnPasses	true	Whether Cypress will process, compress, and upload videos to Cypress Cloud even when all tests in a spec file are passing. This only applies when recording your runs to Cypress Cloud. Turn this off if you'd like to only upload the spec file's video when there are failing tests.

Downloads

Option	Default	Description
downloadsFolder	cypress/downloads	Path to folder where files downloaded during a test are saved
trashAssetsBeforeRuns	true	Whether Cypress will trash assets within the downloadsFolder, screenshotsFolder, and videosFolder before tests run with cypress run.

Browser

Option	Default	Description
chromeWebSecurity	true	Whether to enable Chromium-based browser's Web Security for same-origin policy and insecure mixed content. Read more about Web Security.
blockHosts	null	A String or Array of hosts that you wish to block traffic for. Please read the notes for examples on using this.
firefoxGcInterval	{ "runMode": 1, "openMode": null }	(Firefox 79 and below only) Controls whether Cypress forces Firefox to run garbage collection (GC) cleanup and how frequently. During cypress run, the default value is 1. During cypress open, the default value is null. See full details here.
modifyObstructiveCode	true	Whether Cypress will search for and replace obstructive JS code in .js or .html files. Please read the notes for more information on this setting.
userAgent	null	Enables you to override the default user agent the browser sends in all request headers. User agent values are typically used by servers to help identify the operating system, browser, and browser version. See User-Agent MDN Documentation for example user agent values.

Viewport

Option	Default	Description
viewportHeight	660	Default height in pixels for the application under tests' viewport (Override with cy.viewport() command)
viewportWidth	1000	Default width in pixels for the application under tests' viewport. (Override with cy.viewport() command)

Actionability

Option	Default	Description
animationDistanceThreshold	5	The distance in pixels an element must exceed over time to be considered animating
waitForAnimations	true	Whether to wait for elements to finish animating before executing commands
scrollBehavior	top	Viewport position to which an element should be scrolled before executing commands. Can be 'center', 'top', 'bottom', 'nearest', or false. false disables scrolling.

For more information, see the docs on actionability.

Node version

caution

The nodeVersion configuration option is deprecated and has been removed as an option from current configurations of Cypress 13.0.0 and above. Please remove this option from your configuration file.

Option	Default	Description
nodeVersion	system	Can be system or bundled. If set to system, Cypress will try to use the same Node version that launched Cypress to execute your plugins. If that can't be determined, Cypress will use the Node version bundled with Cypress. If set to bundled Cypress will use the version bundled with Cypress

The Node version is used in Cypress to:

• Build files in the integrationFolder.
• Build files in the supportFile.
• Execute code in the pluginsFile.

Experiments

Configuration might include experimental options currently being tested. See Experiments page.

Overriding Options

Cypress gives you the option to dynamically alter configuration values. This is helpful when running Cypress in multiple environments and on multiple developer machines.

This gives you the option to do things like override the baseUrl or environment variables.

Command Line

When running Cypress from the Command Line you can pass a --config flag.

Examples:

cypress open --config pageLoadTimeout=30000,baseUrl=https://myapp.com

cypress run --config integrationFolder=tests,videoUploadOnPasses=false

cypress run --browser firefox --config viewportWidth=1280,viewportHeight=720

For more complex configuration objects, you may want to consider passing a JSON.stringified object surrounded by single quotes.

cypress open --config '{"watchForFileChanges":false,"testFiles":["**/*.js","**/*.ts"]}'

Runner Specific Overrides

You can override configuration for either the E2E or Component Testing runner using the e2e and component options.

Examples

Component Testing specific viewports in configuration file (cypress.json by default):

{
  "viewportHeight": 600,
  "viewportWidth": 1000,
  "component": {
    "viewportHeight": 500,
    "viewportWidth": 500
  }
}

Testing type specific timeouts in configuration file (cypress.json by default):

{
  "defaultCommandTimeout": 5000,
  "e2e": {
    "defaultCommandTimeout": 10000,
    "slowTestThreshold": 5000
  },
  "component": {
    "slowTestThreshold": 150
  }
}

Plugins

The Cypress plugins file runs in Node environment before the browser running a spec file launches, giving you the most flexibility to set the configuration values. This enables you to do things like:

• Use fs and read off configuration values and dynamically change them.
• Edit the list of browsers found by default by Cypress
• Set config values by reading any custom environment variables

While this may take a bit more work than other options - it yields you the most amount of flexibility and the ability to manage configuration however you'd like.

// cypress/plugins/index.js
module.exports = (on, config) => {
  // modify the config values
  config.defaultCommandTimeout = 10000

  // read an environment variable and
  // pass its value to the specs
  config.env.userName = process.env.TEST_USER || 'Joe'
  // the specs will be able to access the above value
  // by using Cypress.env('userName')

  // IMPORTANT return the updated config object
  return config
}

We've fully documented how to set the configuration values from plugin file here.

Environment Variables

You can also use environment variables to override configuration values. This is especially useful in Continuous Integration or when working locally. This gives you the ability to change configuration options without modifying any code or build scripts.

By default, any environment variable that matches a corresponding configuration key will override the configuration file (cypress.json by default) value.

export CYPRESS_VIEWPORT_WIDTH=800

export CYPRESS_VIEWPORT_HEIGHT=600

We automatically normalize both the key and the value. Cypress will strip off the CYPRESS_, camelcase any keys and automatically convert values into Number or Boolean. Make sure to prefix your environment variables with CYPRESS_ else they will be ignored.

Both options below are valid

export CYPRESS_pageLoadTimeout=100000

export CYPRESS_PAGE_LOAD_TIMEOUT=100000

caution

Environment variables that do not match configuration keys will instead be set as regular environment variables for use in your tests with Cypress.env().

You can read more about Environment Variables.

Test Configuration

We provide two options to override the configuration while your test are running, Cypress.config() and suite-specific or test-specific configuration overrides.

Note: The configuration values below are all writeable and can be changed via per test configuration. Any other configuration values are readonly and cannot be changed at run time.

• animationDistanceThreshold
• baseUrl
• blockHosts
• defaultCommandTimeout
• env note: Provided environment variables will be merged with current environment variables.
• execTimeout
• includeShadowDom
• keystrokeDelay
• numTestsKeptInMemory
• pageLoadTimeout
• redirectionLimit
• requestTimeout
• responseTimeout
• retries
• screenshotOnRunFailure
• scrollBehavior
• slowTestThreshold
• viewportHeight
• viewportWidth
• waitForAnimations

Cypress.config()

You can also override configuration values within your test using Cypress.config().

This changes the configuration for the remaining execution of the current spec file. The values will reset to the previous default values after the spec has complete.

Cypress.config('pageLoadTimeout', 100000)

Cypress.config('pageLoadTimeout') // => 100000

Test-specific Configuration

To apply specific Cypress configuration values to a suite or test, pass a configuration object to the test or suite function as the second argument.

The configuration values passed in will only take effect during the suite or test where they are set. The values will then reset to the previous default values after the suite or test is complete.

Syntax

describe(name, config, fn)
context(name, config, fn)
it(name, config, fn)
specify(name, config, fn)

Suite configuration

If you want to target a suite of tests to run or be excluded when run in a specific browser, you can override the browser configuration within the suite configuration. The browser option accepts the same arguments as Cypress.isBrowser().

You can configure the number of times to retries a suite of tests if they fail during cypress run and cypress open separately.

describe(
  'login',
  {
    retries: {
      runMode: 3,
      openMode: 2,
    },
  },
  () => {
    it('should redirect unauthenticated user to sign-in page', () => {
      // ...
    })

    it('allows user to login', () => {
      // ...
    })
  }
)

Single test configuration

If you want to target a test to run or be excluded when run in a specific browser, you can override the browser configuration within the test configuration. The browser option accepts the same arguments as Cypress.isBrowser().

it('Show warning outside Chrome', { browser: '!chrome' }, () => {
  cy.get('.browser-warning').should(
    'contain',
    'For optimal viewing, use Chrome browser'
  )
})

Resolved Configuration

When you open a Cypress project, clicking on the Settings tab will display the resolved configuration to you. This helps you to understand and see where different values came from. Each set value is highlighted to show where the value has been set via the following ways:

• Default value
• The configuration file
• The Cypress environment file
• System environment variables
• Command Line arguments
• Plugins file

Notes

blockHosts

By passing a string or array of strings you can block requests made to one or more hosts.

To block a host:

• Pass only the host
• Use wildcard * patterns
• Include the port other than 80 and 443
• Do NOT include protocol: http:// or https://

info

Not sure what a part of the URL a host is? Use this guide as a reference.

When blocking a host, we use minimatch to check the host. When in doubt you can test whether something matches yourself.

Given the following URLs:

https://www.google-analytics.com/ga.js

http://localhost:1234/some/user.json

This would match the following blocked hosts:

www.google-analytics.com
*.google-analytics.com
*google-analytics.com

localhost:1234

Because localhost:1234 uses a port other than 80 and 443 it must be included.

caution

Subdomains

Be cautious for URL's which have no subdomain.

For instance given a URL: https://google.com/search?q=cypress

• Matches google.com
• Matches *google.com
• Does NOT match *.google.com

When Cypress blocks a request made to a matching host, it will automatically send a 503 status code. As a convenience it also sets a x-cypress-matched-blocked-host header so you can see which rule it matched.

modifyObstructiveCode

With this option enabled - Cypress will search through the response streams coming from your server on .html and .js files and replace code that matches patterns commonly found in framebusting.

These script patterns are antiquated and deprecated security techniques to prevent clickjacking and framebusting. They are a relic of the past and are no longer necessary in modern browsers. However many sites and applications still implement them.

These techniques prevent Cypress from working, and they can be safely removed without altering any of your application's behavior.

Cypress modifies these scripts at the network level, and therefore there is a tiny performance cost to search the response streams for these patterns.

You can turn this option off if the application or site you're testing does not implement these security measures. Additionally it's possible that the patterns we search for may accidentally rewrite valid JS code. If that's the case, please disable this option.

firefoxGcInterval

caution

The following section only applies if you are using a version of Firefox older than Firefox 80. firefoxGcInterval has no effect if you are using Firefox 80 or newer, since the garbage collection bug was fixed in Firefox 80. It is recommended to upgrade your version of Firefox to avoid this workaround.

Firefox versions 79 and earlier have a bug where it does not run its internal garbage collection (GC) fast enough, which can lead to consuming all available system memory and crashing.

Cypress prevents Firefox from crashing by forcing Firefox to run its GC cleanup routines between tests.

Running GC is an expensive and blocking routine. It adds significant time to the overall run, and causes Firefox to "freeze" for the duration of GC cleanup. This causes the browser not to respond to any user input.

Cypress runs GC cleanup during cypress run only because we don't expect users to interact with the browser - since this is typically run in CI. We've disabled running GC during cypress open because users typically interact with the browser.

Because GC adds additional time to the overall run, we've added the amount of time this routine has taken to the bottom of the Command Log in the Test Runner.

Configuration

You can control how often GC cleanup runs via the firefoxGcInterval configuration value.

firefoxGcInterval controls whether Cypress forces Firefox to run GC cleanup and how frequently.

By default, we force GC cleanup between every test during cypress run, but do not run any GC cleanup during cypress open using the configuration value below:

{
  "firefoxGcInterval": {
    "runMode": 1,
    "openMode": null
  }
}

You can override how often Cypress runs GC cleanup by setting the firefoxGcInterval config value to:

• null, to disable it for both cypress run and cypress open
• a number, which sets the interval for both cypress run and cypress open
• an object to set different intervals for each mode

Examples

Turn off GC cleanup all modes

{
  "firefoxGcInterval": null
}

Run GC cleanup before every other test during cypress run and cypress open

{
  "firefoxGcInterval": 2
}

Run GC cleanup before every 3rd test during cypress run and disable running GC cleanup during cypress open.

{
  "firefoxGcInterval": {
    "runMode": 3,
    "openMode": null
  }
}

isInteractive

You can open Cypress in the interactive mode via the cypress open command, and in run mode via the cypress run command. To detect the mode from your test code you can query the isInteractive property on Cypress.config.

if (Cypress.config('isInteractive')) {
  // interactive "cypress open" mode!
} else {
  // "cypress run" mode
}

Intelligent Code Completion

IntelliSense is available for Cypress while editing your configuration file. Learn how to set up Intelligent Code Completion.

Common problems

baseUrl is not set

Make sure you do not accidentally place the baseUrl or another top-level config variable into the env block. The following configuration is incorrect and WILL NOT WORK:

// ⛔️ DOES NOT WORK
{
  "env": {
    "baseUrl": "http://localhost:3030",
    "FOO": "bar"
  }
}

Solution: place the baseUrl property at the top level, outside the env object.

// ✅ THE CORRECT WAY
{
  "baseUrl": "http://localhost:3030",
  "env": {
    "FOO": "bar"
  }
}

You can also find a few tips on setting the baseUrl in this short video.

Test files not found when using spec parameter

When using the --spec <path or mask> argument, make it relative to the project's folder. If the specs are still missing, run Cypress with DEBUG logs with the following setting to see how the Test Runner is looking for spec files:

DEBUG=cypress:cli,cypress:server:specs

History

Version	Changes
10.0.0	Added page due to deprecation of cypress.json file
8.7.0	Added slowTestThreshold option
8.0.0	Added clientCertificates option
7.0.0	Added e2e and component options.
7.0.0	Added redirectionLimit option.
6.1.0	Added scrollBehavior option.
5.2.0	Added includeShadowDom option.
5.0.0	Added retries configuration.
5.0.0	Renamed blacklistHosts configuration to blockHosts.
4.1.0	Added screenshotOnRunFailure configuration.
4.0.0	Added firefoxGcInterval configuration.
3.5.0	Added nodeVersion configuration.

See also

• Cypress.config() and Cypress.env()
• Environment variables
• Environment Variables recipe
• Extending the Cypress Config File blog post and @bahmutov/cypress-extends package.
• Blog post Keep passwords secret in E2E tests