Cypress allows for greater flexibility in your tests by supporting environment variables to be accessed from a test file but it's not super clear how to import settings from an external source into Cypress and have them available to your tests.

Command Line

Cypress does support adding environment variables from the command line:

npx cypress run --env deployment=QA
npx cypress run --env deployment=PRODUCTION

Which turns up in the test like this:

const deployment = Cypress.env("deployment");

Configuration

A less well known way of adding environment variables is from within the cypress.config.js file and the setupNodEvents handler in the e2e block within defineConfig. As in the previous example, variables created this way are available in the tests using the Cypress.env function.

Here I am reading values from a postman environment file (currently moving from Postman to Cypress for API testing) and exposing the values within that file as environment variables.

cypress.Config.js

const {
defineConfig
} = require("cypress");
const fs = require('fs');
const path = require('path');

module.exports = defineConfig({
e2e: {
setupNodeEvents(on, config) {

            // .. code to resolve the path to the env file...
            const data = fs.readFileSync(pathToFile, 'utf-8');
            const postmanConfig = JSON.parse(data);

            postmanConfig.values.forEach(x => {
                config.env[x.key] = x.value;
            });

            return config;
        },
    },

});