How is TestNG different from Selenium WebDriver?

Selenium is an automation tool using which we can automate web-based applications. In order to add testing capabilities in the Test Automation suites – Selenium is clubbed with TestNG. With TestNG, we can have different features in our automation suite like different types of assertions, reporting, parallel execution, and parameterization, etc.
In short, for doing Automation Testing, Selenium helps with ‘automation’ and TestNG helps with ‘testing’ capabilities.