What is a stealth browser?
A stealth browser is a real browser engine, usually Chromium or Firefox, that you drive from code with Playwright, Puppeteer or Selenium, but with the signs of automation taken out. It renders pages and runs JavaScript like any browser. The difference is in what a page can learn about it: a stock browser under automation announces itself in a dozen small ways, and a stealth browser tries not to.
Those small ways sit in three layers. The driver: automation flags, ChromeDriver's leftovers, and navigator.webdriver. The control session: side effects of the DevTools Protocol, such as the Runtime.enable leak and scripts injected into every page. The fingerprint: canvas, WebGL, fonts, screen, hardware and the TLS handshake, all of which describe the machine. A tool that fixes one layer leaves the other two as they were.
That is the easiest way to sort the tools. JavaScript plugins such as puppeteer-extra-plugin-stealth, playwright-stealth and selenium-stealth override values from inside the page. Driver patches such as Patchright and rebrowser-patches change how the automation library talks to the browser. CDP clients such as nodriver and Zendriver skip WebDriver entirely. Engine-level browsers such as Camoufox (Firefox) and Clearcote (Chromium) change the browser itself.
The layers are not interchangeable. A plugin can set navigator.webdriver to false, but the override is itself visible: the replaced function doesn't stringify as native code, and a Web Worker still reads the original value. A driver patch hides the session well, but the browser underneath still reports your real hardware, which on a server means a software GPU and a Linux font set. Only a change inside the engine alters what every frame, worker and network connection reports.
No stealth browser makes automation invisible. Detection also looks at IP reputation, request patterns and behaviour, none of which a browser controls. What a good stealth browser does is make the browser itself unremarkable: one consistent machine, in every realm, with a handshake that matches its user agent.
Clearcote is the engine-level option for Chromium: an open build with readable patches and reproducible builds, a latest build free with GitHub, and ordinary Playwright or Puppeteer on top. You can see how any browser measures up, including your own, with the Clearcote fingerprint audit, and compare the options side by side on the alternatives page.