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Environment Variables

caution
Difference between OS-level and Cypress environment variables

In Cypress, "environment variables" are variables that are accessible via Cypress.env. These are not the same as OS-level environment variables. However, it is possible to set Cypress environment variables from OS-level environment variables.

Environment variables are useful when:

  • Values are different across developer machines.
  • Values are different across multiple environments: (dev, staging, qa, prod)
  • Values change frequently and are highly dynamic.

Environment variables can be changed easily - especially when running in CI.

Instead of hard coding this in your tests:​

cy.request('https://api.acme.corp') // this will break on other environments

We can move this into a Cypress environment variable:​

cy.request(Cypress.env('EXTERNAL_API')) // points to a dynamic env var
info
Using 'baseUrl'

Environment variables are great at pointing to external services and servers, or storing password or other credentials.

However, you do not need to use environment variables to point to the origin and domain under test. Use baseUrl instead of environment variables.

cy.visit() and cy.request() are automatically prefixed with this value - avoiding the need to specify them.

baseUrl can be set in the Cypress configuration file - and then you can set an environment variable in your OS to override it like shown below.

CYPRESS_BASE_URL=https://staging.app.com cypress run

Setting​

There are different ways to set environment variables. Each has a slightly different use case.

To summarize you can:

Don't feel obligated to pick just one method. It is common to use one strategy for local development but another when running in CI.

When your tests are running, you can use the Cypress.env function to access the values of your environment variables.

Option #1: configuration file​

Any key/value you set in your Cypress configuration under the env key will become an environment variable.

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  projectId: '128076ed-9868-4e98-9cef-98dd8b705d75',
  env: {
    login_url: '/login',
    products_url: '/products',
  },
})

Test file​

Cypress.env() // {login_url: '/login', products_url: '/products'}
Cypress.env('login_url') // '/login'
Cypress.env('products_url') // '/products'

Overview​

tip
Benefits
  • Great for values that need to be checked into source control and remain the same on all machines.
danger
Downsides
  • Only works for values that should be the same on across all machines.

Option #2: cypress.env.json​

You can create your own cypress.env.json file that Cypress will automatically check. Values in here will overwrite conflicting environment variables in your Cypress configuration.

This strategy is useful because if you add cypress.env.json to your .gitignore file, the values in here can be different for each developer machine.

{
  "host": "veronica.dev.local",
  "api_server": "http://localhost:8888/api/v1/"
}

From test file​

Cypress.env() // {host: 'veronica.dev.local', api_server: 'http://localhost:8888/api/v1'}
Cypress.env('host') // 'veronica.dev.local'
Cypress.env('api_server') // 'http://localhost:8888/api/v1/'

An Overview​

tip
Benefits
  • Dedicated file just for environment variables.
  • Enables you to generate this file from other build processes.
  • Values can be different on each machine (if not checked into source control).
  • Supports nested fields (objects), e.g. { testUser: { name: '...', email: '...' } }.
danger
Downsides
  • Another file you have to deal with.
  • Overkill for 1 or 2 environment variables.

Option #3: CYPRESS_*​

Any exported environment variables set on the command line or in your CI provider that start with either CYPRESS_ or cypress_ will automatically be parsed by Cypress.

danger

The environment variable CYPRESS_INTERNAL_ENV is reserved and should not be set.

Overriding configuration options​

Environment variables that match a corresponding configuration option will override any value set in the Cypress configuration.

info

Cypress automatically normalizes both the key and the value. The leading CYPRESS_ or cypress_ is removed and the remaining name is camelCased, while values are converted to Number or Boolean wherever possible.

For example, these enviroment variables in the command line will override any viewportWidth or viewportHeight options set in the Cypress configuration:

export CYPRESS_VIEWPORT_WIDTH=800
export CYPRESS_VIEWPORT_HEIGHT=600

Overriding environment variables​

Environment variables that do not match configuration options will be set as environment variables for use in tests with Cypress.env(), and will override any existing values in the Cypress configuration env object and cypress.env.json files.

info

Cypress automatically removes the leading CYPRESS_ or cypress_ from any environment variable name specified in this way.

For example, these environment variables in the command line:

export CYPRESS_HOST=laura.dev.local
export cypress_api_server=http://localhost:8888/api/v1/

Will yield these results inside a test file:

Cypress.env() // {HOST: 'laura.dev.local', api_server: 'http://localhost:8888/api/v1'}
Cypress.env('HOST') // 'laura.dev.local'
Cypress.env('api_server') // 'http://localhost:8888/api/v1/'

Overview:​

tip
Benefits
  • Quickly export some values.
  • Can be stored in your bash_profile.
  • Allows for dynamic values between different machines.
  • Especially useful for CI environments.
danger
Downsides
  • Not as obvious where values come from versus the other options.
  • No support for nested fields.

Option #4: --env​

You can pass in environment variables as options when using the CLI tool.

Values here will overwrite all other conflicting environment variables.

You can use the --env argument for cypress run.

caution

Multiple values must be separated by a comma, not a space. In some shells, like Windows PowerShell, you may need to surround the key/value pair with quotes: --env "cyuser=dummyUser,cypassword=dummyPassword".

From the command line or CI​

cypress run --env host=kevin.dev.local,api_server=http://localhost:8888/api/v1

Test file:​

Cypress.env() // {host: 'kevin.dev.local', api_server: 'http://localhost:8888/api/v1'}
Cypress.env('host') // 'kevin.dev.local'
Cypress.env('api_server') // 'http://localhost:8888/api/v1/'

Overview -​

tip
Benefits
  • Does not require any changes to files or configuration.
  • More clear where environment variables come from.
  • Allows for dynamic values between different machines.
  • Overwrites all other forms of setting env variables.
danger
Downsides
  • Pain to write the --env options everywhere you use Cypress.
  • No support for nested fields.

Option #5: Test Configuration​

You can set environment variables for specific suites or tests by passing the env values to the test configuration.

Suite of test configuration​

// change environment variable for single suite of tests
describe(
  'test against Spanish content',
  {
    env: {
      language: 'es',
    },
  },
  () => {
    it('displays Spanish', () => {
      cy.visit(`https://docs.cypress.io/${Cypress.env('language')}/`)
      cy.contains('¿Por qué Cypress?')
    })
  }
)

Single test configuration​

// change environment variable for single test
it(
  'smoke test develop api',
  {
    env: {
      api: 'https://dev.myapi.com',
    },
  },
  () => {
    cy.request(Cypress.env('api')).its('status').should('eq', 200)
  }
)

// change environment variable for single test
it(
  'smoke test staging api',
  {
    env: {
      api: 'https://staging.myapi.com',
    },
  },
  () => {
    cy.request(Cypress.env('api')).its('status').should('eq', 200)
  }
)

Overview​

tip
Benefits
  • Only takes effect for duration of suite or test.
  • More clear where environment variables come from.
  • Allows for dynamic values between tests

Overriding Configuration​

If your environment variables match a standard configuration key, then instead of setting an environment variable they will instead override the configuration value.

Change the baseUrl configuration value / not set env var in Cypress.env()

export CYPRESS_BASE_URL=http://localhost:8080

'foo' does not match config / sets env var in Cypress.env()

export CYPRESS_FOO=bar

You can read more about how environment variables can change configuration here.

See also​

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