The Appium server is used to interact with different platform such as Android and iOS. It creates a session to interact with mobile apps, which are not supported on any platform. It is an HTTP server written in Node.js and uses the same concept as the Selenium Server, which identifies the HTTP requests from the client libraries and sends these requests to the appropriate platform. To start the Appium server, users need to download the source or install it directly from npm.
One of the biggest advantages of Appium is because it is simply a REST API at its core, the code you use to interact with it is written in a number of languages such as Java, C#, Ruby, Python, and others.
Appium extends the WebDriver client libraries and adds the extra commands in it to work with mobile devices. It provides client libraries that support Appium extensions to the WebDriver protocol. Because of these extensions to the protocol, it is important to use Appium-specific client libraries to write automation tests or procedures, instead of generic WebDriver client libraries.
These libraries wrap standard Selenium client libraries to provide all the regular selenium commands dictated by the JSON Wire protocol, and add extra commands related to controlling mobile devices, such as multi-touch gestures and screen orientation.
Appium has language binding for:
- Objective C
Appium client libraries implement the Mobile JSON Wire Protocol, and elements of the W3C Webdriver spec. The Appium server itself defines custom extensions to the official protocols, giving Appium users helpful access to various device behaviors (such as installing/uninstalling apps during the course of a test session).