cypress-io/cypress-realworld-app

This is a practice payment application built by the team behind Cypress, a popular tool for automated browser testing. The app itself mimics the kind of thing you might see in a real product: users can log in, send money to each other, view transaction history, and manage a basic account. It is not meant to handle real payments and is not intended for production use. Its purpose is to give developers a realistic codebase to learn and experiment with testing. The reason the app exists is to show how Cypress tests work in a real scenario, not a toy example. Developers can open the test suite and see how to write tests that click through the browser, how to test API responses directly, how to test individual UI components in isolation, and how to track which lines of code the tests actually exercise. All four of those approaches are demonstrated in the same project. The app runs locally on your machine. It uses a React frontend, an Express backend, and a local JSON file as its database instead of a real database server. That means you can clone the repository, install dependencies with Yarn, and start everything with a single command. The database refills itself with sample data each time you restart the app, so tests always start from a known state. Several login options are included, ranging from a built-in local account system to integrations with third-party identity providers like Auth0, Okta, and Amazon Cognito. Each variation has its own startup command and a linked guide so you can practice testing different authentication flows. The project is maintained by Cypress and is used in their official documentation and tutorials as the reference example for real-world testing patterns.