Q4 of 37 · Selenium
What is the difference between Selenium IDE, Selenium WebDriver, and Selenium Grid?
Short answer
Short answer: IDE is a record-and-playback browser extension for quick scripts. WebDriver is the programmatic browser-control library you build real test suites against. Grid is the distributed execution layer that runs WebDriver tests in parallel across machines and browsers.
Detail
These three tools form a Selenium stack — used together or independently.
Selenium IDE is a browser extension (Chrome / Firefox) that records your clicks and types into a playback script. It's great for prototyping a flow, training a non-technical tester, or generating a starting skeleton, but the recorded scripts are brittle (XPath-by-position locators, no Page Objects, no waits beyond auto-pauses). Production teams rarely run IDE scripts in CI.
Selenium WebDriver is the library that ~99% of "Selenium tests" actually use. You write code in your language of choice, structure it however you want (Page Objects, fixtures, runners), and run it against any browser that ships a WebDriver-compatible driver. This is the engine for serious automation.
Selenium Grid is the orchestration layer for running WebDriver tests in parallel. A hub receives requests for sessions, a pool of nodes hosts browsers, and the hub routes each test to a free node. You'd use Grid when:
- A single machine can't run enough sessions in parallel.
- You need cross-browser/cross-OS coverage (a Windows node for Edge, a Mac node for Safari).
- You're standing up an internal Sauce Labs / BrowserStack equivalent.
A clean way to remember: IDE is the prototype; WebDriver is the engine; Grid is the runway.