What is Saucelabs?
Sauce Labs is a cloud platform for executing automated and manual mobile and web tests. Sauce Labs supports running automated tests with Selenium WebDriver (for web applications) and Appium (for native and mobile web applications).
Why do we need Saucelabs?
Straight forward answer : Browser Compatibility. We need to test all our testcases in various versions of browsers and various platforms too. We can’t install all those stuff in our local box. Now this Saucelabs plays a major role.