Headless Browser
A headless browser runs without a visible graphical interface — executing the same rendering and JavaScript engine as a normal browser, but with no window drawn on screen. It's used heavily in test automation and CI pipelines, where nobody needs to watch the browser and speed and resource efficiency matter more.
Running tests headlessly is significantly faster and lighter than rendering a full visible browser window, which matters when a CI pipeline might run hundreds of browser-based tests in parallel across many machines — headless mode avoids the overhead of actually drawing pixels nobody will look at.
Nearly all modern browser engines (Chromium, Firefox, WebKit) support a headless mode natively, and frameworks like Playwright default to running headless in CI while making it trivial to toggle to headed mode locally for debugging a failing test visually.
