Why Almost Every Web Browser Runs on Just 3 Engines

Why is it almost impossible to build a new web browser? Most browsers you know, like Chrome, Edge, Opera, Brave and Samsung Internet, are built on Google's free, open Chromium project and its browser engine, Blink. Among the big browsers, only two use a different engine: Safari runs on Apple's WebKit and Firefox runs on Mozilla's Gecko. Here's how it got this way, who pays for it, and what a browser engine actually does every time you open a page. In this video: Chrome, Edge, Opera, Brave, Samsung Internet and Vivaldi are all Chromium inside, and so are new AI browsers like Comet, Dia and Opera Neon. About two out of three people browse with Chrome, and about three out of four with a Chromium browser. On iPhone, Apple's rules make Chrome, Firefox and every other big browser run on Safari's engine. How we got here: the very first web browser (1990, at CERN, on a NeXT computer), Netscape, Internet Explorer reaching about 95% of web browsing by 2002, Netscape's code becoming Mozilla and Firefox, the small KHTML engine becoming Apple's WebKit, and Google splitting off Blink in 2013. Opera and Microsoft gave up their own engines, so today almost every browser runs on one of just three. Why Chrome still introduces itself to every website as "Mozilla", "AppleWebKit", "KHTML, like Gecko" and "Safari". The money: most of Firefox's money comes from its rival, Google (about half a billion dollars a year for default search), Google paid Apple about $20 billion in 2022 alone, mostly to be Safari's default search, and in 2025 an AI company offered $34.5 billion for Chrome. Google didn't sell. What the engine does when you open a page: it downloads the HTML, builds the DOM, works out style and layout, paints the pixels for your graphics chip to stack about 60 times a second, runs JavaScript as fast machine code, and keeps sites in separate sandboxes (one reason Chrome uses so much RAM). Bonus: the first version of JavaScript was written in about 10 days. How big it is: more than 35 million lines of code (more than the whole Linux kernel), over 2 million shared tests, browsers trying hard never to break old pages, and a new Chrome version every two weeks. Can anyone build a new one? Ladybird, a small non-profit team with no ads and no search deals, has spent years building a new engine from scratch, and it's still not ready for everyday use. And no, AI can't just build one. Not yet. Subscribe for more of the hidden engineering you use every day. CHAPTERS 0:00 Millions of apps, only a few browsers 0:20 One project runs most browsers 1:09 How we got here (1990 → today) 2:10 Chrome's strange name tag 2:35 Google pays its rivals 3:04 What a browser engine does 4:11 How big a browser is 4:53 Can anyone build a new one? SOURCES Browser market share (StatCounter, Sept 2026): https://gs.statcounter.com/browser-ma... Mozilla 2024 audited financials: https://stateof.mozilla.org/pdf/Mozil... Blink, Chromium's rendering engine: https://www.chromium.org/blink/ WebKit and its KHTML roots: https://en.wikipedia.org/wiki/WebKit Google paid Apple $20B in 2022 (Bloomberg Law): https://news.bloomberglaw.com/antitru... Site Isolation in Chrome (Google Security Blog): https://security.googleblog.com/2018/... Web Platform Tests: https://wpt.fyi/ Ladybird: https://ladybird.org/ The first website (CERN): https://info.cern.ch/hypertext/WWW/Th... The first web browser (Tim Berners-Lee): https://www.w3.org/People/Berners-Lee... Chrome's two-week release cycle: https://developer.chrome.com/blog/chr... User-Agent string (MDN): https://developer.mozilla.org/en-US/d... #WebBrowser #Chromium #BrowserEngine