The Appium is the good test automation framework for both platform IOS and
Android. The major advantage is it doesn’t need to change the source code
of the test target and progam test code with any script language ( Javascript, Python, Ruby and etc ).

The Appium framework

C/S Architecture
The core of Appium is web service，which provide the REST API。It can listen for the connection from client, monitor the command and execute them on the client ，then it will response with to client with HTTP response。Actually，the architecture provide much more possiblilities：for example, we can implement our test code with any languages, or we can deploy the server in different mahcines so that we can use Cloud service such as Sauce Labs to excute the command.

Appium Server
Appium server is written by nodejs.

Appium Client
Appium has many support client for Java, Ruby, Python, PHP, JavaScript and C#，all these library extend the WebDriver in Appium.

Appium Driver
Appium has the Driver installed on Android or IOS to handle the command from Server and execute them on Mobile device.

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Extend on Appium Server

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Extend on Appium Android Driver

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Result

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