Appium
Appium is an open-source framework for automating native, hybrid, and mobile web app testing on iOS and Android using a single, cross-platform API. It works by translating standard automation commands (via the WebDriver protocol) into platform-specific instructions each OS understands.
Appium's central design choice is not requiring any code to be added to the app under test — it drives the app the same way a real user would, through the OS's own accessibility and UI automation layers, which means the same tests can validate the actual production build rather than a specially instrumented one.
Because it speaks the WebDriver protocol, teams already familiar with Selenium's API model can pick up Appium's syntax quickly, and many test frameworks that support Selenium support Appium with minimal changes — a deliberate design decision to lower the switching cost for automation engineers moving between web and mobile.
