Mozilla Firefox

In short: An open-source browser from the Mozilla Foundation, with its own rendering engine (Gecko) instead of the Chromium base used by many other browsers.

In more detail: Often highlighted for its focus on privacy and standards compliance. Its independence from Chromium is relevant for web-standard diversity: if all browsers were based on the same engine, a single vendor would effectively have control over web standards.

In Depth

The last independent engine

Firefox is today one of only three relevant independent rendering engines on the web left (besides Chromium and Apple’s WebKit) — the overwhelming majority of other browsers (Edge, Brave, Opera, Vivaldi and many more) are now based directly on Chromium. This concentration is viewed critically by many in the web development community: ideally, web standards emerge through consensus among several independent implementations in the W3C/WHATWG standardisation process. If one engine becomes dominant enough, its actual behaviour can effectively become the de-facto standard, regardless of the official process — websites then get unknowingly built “against Chrome” instead of “against the standard”, which structurally weakens other engines’ position (an effect critics often compare to Internet Explorer’s historical dominance in the early 2000s).

Origin and business model

Firefox traces back to the Mosaic/Netscape legacy: after Netscape lost against Microsoft’s Internet Explorer, its source code was opened in 1998 as the Mozilla project, from which Firefox later emerged (2004) as a standalone, leaner browser that gave IE serious competition for the first time. Firefox is developed by the non-profit Mozilla Foundation (via its commercial subsidiary Mozilla Corporation) and finances itself mainly through search engine partnerships — Google pays Mozilla to be set as the default search engine in the browser, which makes up most of Mozilla’s budget (a dependency repeatedly criticised as risky, since Mozilla’s biggest competitor in the browser market is at the same time its most important funder).

Differentiation via privacy and developer tools

Besides privacy features (a built-in tracker blocker, stricter cookie isolation between websites, “Enhanced Tracking Protection”), Firefox is also popular among web developers for its developer tools and early/thorough support of new CSS features — Firefox has long been considered the reference implementation among browser DevTools especially for the CSS Grid layout inspector. Firefox thereby deliberately positions itself as a privacy-friendly, non-commercial alternative to the big tech-corporation browsers (Chrome/Google, Edge/Microsoft, Safari/Apple).

See also: Browser, Google Chrome, Microsoft Edge