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Configuration API

Cypress enables you to dynamically modify configuration values and environment variables from your Cypress configuration.



⚠️ This code is part of the setupNodeEvents function and thus executes in the Node environment. You cannot call Cypress or cy commands in this function, but you do have the direct access to the file system and the rest of the operating system.

To modify configuration, you return a config object from setupNodeEvents within this exported function.

const { defineConfig } = require('cypress')

module.exports = defineConfig({
// setupNodeEvents can be defined in either
// the e2e or component configuration
e2e: {
setupNodeEvents(on, config) {
console.log(config) // see everything in here!

// modify config values
config.defaultCommandTimeout = 10000
config.baseUrl = ''

// modify env var value
config.env.ENVIRONMENT = 'staging'

// IMPORTANT return the updated config object
return config

Whenever you return an object from your setupNodeEvents function, Cypress will take this and "diff" it against the original configuration and automatically set the resolved values to point to what you returned.

If you don't return an object, then configuration will not be modified.


The config object also includes the following extra values that are not part of the standard configuration. These values are read only and cannot be modified from the setupNodeEvents function in the Cypress configuration.

  • configFile: The absolute path to the Cypress configuration file. See the --config-file and configFile docs for more information on this value.
  • projectRoot: The absolute path to the root of the project (e.g. /Users/me/dev/my-project)

Resolved values will show up in the "Settings" tab.

Resolved configuration in the Desktop app


Additionally, Cypress will respect and await promises you return. This enables you to perform asynchronous tasks and eventually resolve with the modified configuration object. See the example on switching between multiple configuration files for a full example.


Customize available browsers

The configuration includes the list of browsers found on your system that are available to Cypress. You can, for example, change or augment that list for different testing purposes.


Read our full guide on Launching Browsers for more information on how this works.

Switch between multiple configuration files



Configuring plugins via cypress/plugins/index.js is no longer supported as of Cypress version 10.0.0.

We recommend that you update your configuration. Please see the plugins guide and the migration guide for more information on how to update your configuration.

This means you can do things like store multiple configuration files and switch between them like:


How you choose to organize your configuration and environment variables is up to you.

// promisified fs module
const fs = require('fs-extra')
const path = require('path')

function getConfigurationByFile(file) {
const pathToConfigFile = path.resolve('..', 'config', `${file}.json`)

return fs.readJson(pathToConfigFile)

// plugins file
module.exports = (on, config) => {
// accept a configFile value or use development by default
const file = config.env.configFile || 'development'

return getConfigurationByFile(file)

You could now swap out configuration + environment variables like so:

cypress run
cypress run --env configFile=qa
cypress run --env configFile=staging
cypress run --env configFile=production

Each of these environments would read in the configuration at these files:


This would enable you to do things like this:

// cypress/config/development.json

"baseUrl": "http://localhost:1234",
"env": {
"something": "development"
// cypress/config/qa.json

"baseUrl": "",
"env": {
"something": "qa"
// cypress/config/staging.json

"baseUrl": "",
"env": {
"something": "staging"
// cypress/config/production.json

"baseUrl": "",
"env": {
"something": "production"

This is a less complicated example. Remember - you have the full power of Node at your disposal.

How you choose to edit the configuration is up to you. You don't have to read off of the file system - you could store them all in memory inside of setupNodeEvents if you wanted.

Test Type-Specific Plugins

You can access the type of tests running via the config.testingType property. The testing type is either e2e or component depending on if the E2E Testing or Component Testing type was selected in the Cypress Launchpad. This allows you to configure test type-specific plugins.


7.0.0Added testingType property to config.

See also