The first time you open Cypress Test Runner, 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 the Cypress Dashboard the projectId will be written in this file too.


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.


baseUrlnullURL 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
includeShadowDomfalseWhether to traverse shadow DOM boundaries and include elements within the shadow DOM in the results of query commands (e.g. cy.get())
numTestsKeptInMemory50The 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.
portnullPort used to host Cypress. Normally this is a randomly generated port
redirectionLimit20The number of times that the application under test can redirect before erroring.
reporterspecThe reporter used during cypress run
reporterOptionsnullThe 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.
watchForFileChangestrueWhether Cypress will watch and restart tests on test file changes


defaultCommandTimeout4000Time, in milliseconds, to wait until most DOM based commands are considered timed out
execTimeout60000Time, in milliseconds, to wait for a system command to finish executing during a cy.exec() command
taskTimeout60000Time, in milliseconds, to wait for a task to finish executing during a cy.task() command
pageLoadTimeout60000Time, 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.
requestTimeout5000Time, in milliseconds, to wait for a request to go out in a cy.wait() command
responseTimeout30000Time, 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

Folders / Files

downloadsFoldercypress/downloadsPath to folder where files downloaded during a test are saved
fileServerFolderroot project folderPath to folder where application files will attempt to be served from
fixturesFoldercypress/fixturesPath to folder containing fixture files (Pass false to disable)
ignoreTestFiles*.hot-update.jsA 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 to test what files would match.
integrationFoldercypress/integrationPath to folder containing integration test files
pluginsFilecypress/plugins/index.jsPath to plugins file. (Pass false to disable)
screenshotsFoldercypress/screenshotsPath to folder where screenshots will be saved from cy.screenshot() command or after a test fails during cypress run
supportFilecypress/support/index.jsPath 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
videosFoldercypress/videosPath to folder where videos will be saved during cypress run


screenshotOnRunFailuretrueWhether Cypress will take a screenshot when a test fails during cypress run.
screenshotsFoldercypress/screenshotsPath to folder where screenshots will be saved from cy.screenshot() command or after a test fails during cypress run
trashAssetsBeforeRunstrueWhether 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.


trashAssetsBeforeRunstrueWhether Cypress will trash assets within the downloadsFolder, screenshotsFolder, and videosFolder before tests run with cypress run.
videoCompression32The 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).
videosFoldercypress/videosWhere Cypress will automatically save the video of the test run when tests run with cypress run.
videotrueWhether Cypress will capture a video of the tests run with cypress run.
videoUploadOnPassestrueWhether Cypress will process, compress, and upload videos to the Dashboard even when all tests in a spec file are passing. This only applies when recording your runs to the Dashboard. Turn this off if you'd like to only upload the spec file's video when there are failing tests.


downloadsFoldercypress/downloadsPath to folder where files downloaded during a test are saved
trashAssetsBeforeRunstrueWhether Cypress will trash assets within the downloadsFolder, screenshotsFolder, and videosFolder before tests run with cypress run.


chromeWebSecuritytrueWhether to enable Chromium-based browser's Web Security for same-origin policy and insecure mixed content. Read more about Web Security.
blockHostsnullA 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.
modifyObstructiveCodetrueWhether Cypress will search for and replace obstructive JS code in .js or .html files. Please read the notes for more information on this setting.
userAgentnullEnables 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.


viewportHeight660Default height in pixels for the application under tests' viewport (Override with cy.viewport() command)
viewportWidth1000Default width in pixels for the application under tests' viewport. (Override with cy.viewport() command)


animationDistanceThreshold5The distance in pixels an element must exceed over time to be considered animating
waitForAnimationstrueWhether to wait for elements to finish animating before executing commands
scrollBehaviortopViewport 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

nodeVersionbundledIf set to system, Cypress will try to find a Node executable on your path to use when executing your plugins. Otherwise, Cypress will use the Node version bundled with Cypress.

The Node version printed in the Node.js Version panel is used in Cypress to:

Cypress comes automatically bundled with a set Node version by default. You can see the bundled version by running the cypress version command, for example:

npx cypress version
Cypress package version: 6.2.1
Cypress binary version: 6.2.1
Electron version: 11.1.1
Bundled Node version: 12.18.3

You may want to use a different Node version if the code executing from the plugins file requires features present in a different Node version from the Node version bundled with Cypress. You can use the Node version detected on your system by setting the nodeVersion configuration to system. For example, you need to use the system Node if you want to load node-sass or sqlite3 modules from your plugins file.

Node version in Settings in Test Runner


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.


cypress open --config pageLoadTimeout=30000,baseUrl=
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.


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

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

E2E specific timeouts in configuration file (cypress.json by default):

  "defaultCommandTimeout": 5000,
  "e2e": {
    "defaultCommandTimeout": 10000


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.


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


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

Cypress.config('pageLoadTimeout', 100000)

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

Test 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.

Note: Some configuration values are readonly and cannot be changed via test configuration. The following configuration values can be changed via per test configuration:
  • animationDistanceThreshold
  • baseUrl
  • browser note: filters whether the tests or a suite of tests runs depending on the current browser
  • defaultCommandTimeout
  • execTimeout
  • env note: Provided environment variables will be merged with current environment variables.
  • includeShadowDom
  • requestTimeout
  • responseTimeout
  • retries
  • scrollBehavior
  • viewportHeight
  • viewportWidth
  • waitForAnimations

Suite configuration

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

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

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

You can set the baseUrl value for a single test:

it('navigates through the tab',
  { baseUrl: Cypress.env('APP_AT') },
  () => {

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' }, () => {
    '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:

See resolved configuration



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

To see a working example of this please check out our Stubbing Google Analytics Recipe.

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://

Given the following URLs:


This would match the following blocked hosts:


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

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.

Network tab of dev tools with analytics.js request selected and the response header highlighted


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.


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.

GC duration shown


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:


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


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:

  "env": {
    "baseUrl": "http://localhost:3030",
    "FOO": "bar"

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

  "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:



8.0.0Added clientCertificates option
7.0.0Added e2e and component options.
7.0.0Added redirectionLimit option.
6.1.0Added scrollBehavior option.
5.2.0Added includeShadowDom option.
5.0.0Added retries configuration.
5.0.0Renamed blacklistHosts configuration to blockHosts.
4.1.0Added screenshotOnRunFailure configuration.
4.0.0Added firefoxGcInterval configuration.
3.5.0Added nodeVersion configuration.

See also