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Automation

What Is Selenium?

Selenium is an open-source browser automation framework that uses the WebDriver protocol to control browsers programmatically, enabling automated testing of web applications across multiple browsers and programming languages.

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In Depth

Selenium has been the standard browser automation tool since 2004. It consists of several components: WebDriver (the core API for controlling browsers), Selenium Grid (for running tests in parallel across machines), and Selenium IDE (a record-and-playback tool).

Selenium communicates with browsers through the W3C WebDriver protocol via browser-specific drivers (ChromeDriver, GeckoDriver, etc.). This protocol-based approach gives Selenium the widest browser and language support of any automation framework: Java, Python, C#, Ruby, JavaScript, and Kotlin.

In 2026, Selenium remains widely used in enterprise environments with existing test suites, Java-based organizations, and teams that need Ruby or Kotlin support. However, for new projects, Playwright has overtaken Selenium due to its auto-waiting, faster execution, and superior debugging tools.

Key Selenium concepts to know: explicit waits (WebDriverWait with expected conditions), the page object model for maintainability, Selenium Grid for parallel execution, and Selenium Manager for automatic driver management.

Why Interviewers Ask About This

Selenium remains one of the most asked-about frameworks in QA interviews, especially at enterprise companies. Even if you prefer Playwright, demonstrating Selenium knowledge shows breadth and the ability to work with legacy codebases.

Example Scenario

A financial services company has 2,000 Selenium tests in Java that run nightly on Selenium Grid. The suite covers regulatory compliance flows that rarely change. The team maintains the suite while building new tests in Playwright, running both frameworks in the same CI pipeline.

Interview Tip

Show you know both Selenium and modern alternatives. Discuss Selenium's strengths (language breadth, enterprise adoption) and limitations (no auto-waiting, driver management complexity). If asked to compare, be fair to both.

Related Terms

Explore related glossary terms to deepen your understanding.

PlaywrightPlaywright is an open-source browser automation framework developed by Microsoft that enables reliable end-to-end testing across Chromium, Firefox, and WebKit with a single API.
Page Object Model (POM)The Page Object Model (POM) is a design pattern in test automation where each web page or component is represented by a class that encapsulates its elements and interactions, separating test logic from UI details.
Test AutomationTest automation is the practice of using software tools and scripts to execute tests, compare actual outcomes to expected outcomes, and report results — replacing or augmenting manual test execution.
End-to-End TestingEnd-to-end (E2E) testing validates complete user workflows from start to finish, simulating real user behavior across the entire application stack — frontend, backend, database, and external integrations.
Flaky TestA flaky test is an automated test that produces inconsistent pass/fail results across multiple runs without any changes to the source code or test itself.

Related Resources

Dive deeper with these related interview prep pages.

Selenium Interview QuestionsPlaywright vs Selenium 2026Selenium Resources & Toolkits

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Written by Aston Cook, Senior QA EngineerLast updated: March 2026