Selenium Simplified — How Selenium Works Internally

When people start learning Selenium, they usually write their first script and see a browser open automatically. But a common question appears immediately: “How is my code controlling the browser?” Understanding this will make Selenium much easier to learn. So before jumping into automation scripts, let's understand how Selenium works internally. What is Selenium? Selenium is a browser automation tool used to simulate real user actions like: Opening a website Clicking buttons Typing into fields Submitting forms Validating UI behavior Because of this, Selenium is widely used for: Web application testing Regression testing Automated UI validation But Selenium itself does not control the browser directly . There is a small chain of components involved. The Selenium Architecture (How Everything Connects) When you run a Selenium script, the following flow happens: Your Test Code ↓ Selenium WebDriver API ↓ Browser Driver (ChromeDriver / GeckoDriver) ↓ Actual Browser Let’s break this down. 1.