# What is the Chrome DevTools Protocol (CDP)? | SoftGlaze Browser glossary

> The Chrome DevTools Protocol lets programs control Chromium over a WebSocket. How CDP works, why it can be detected, and how SoftGlaze uses it.

- Canonical URL: https://browser.softglaze.com/glossary/chrome-devtools-protocol
- Last updated 2026-11-07

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[Automation and AI](https://browser.softglaze.com/glossary?category=automation-and-ai)

## Chrome DevTools Protocol (CDP)

Also called CDP, DevTools Protocol, remote debugging, wsEndpoint, remote-debugging-port

Definition

The Chrome DevTools Protocol (CDP) is the interface Chromium-based browsers expose for debugging and control, a set of commands and events sent as JSON over a WebSocket, which DevTools, Puppeteer and many automation tools use.

Last updated 7 November 2026

### How it works

Start Chromium with a remote debugging port and it accepts WebSocket connections. A client sends commands grouped in domains, such as `Page.navigate`, `Runtime.evaluate`, `Network.setCookie` or `Emulation.setTimezoneOverride`, and receives events back. The browser-level WebSocket address, often called the `wsEndpoint`, is what libraries like Puppeteer connect to. The same protocol powers the DevTools panel itself.

### Why it matters when you run several accounts

CDP is how most tools automate Chromium and how many apps set a profile’s values. It is also observable. Some commands, such as enabling the `Runtime` domain, have side effects a page can notice, and anti-bot scripts probe for them. The less an outside tool does over CDP while a page is loaded, the less there is to notice.

### How SoftGlaze Browser handles it

SoftGlaze Browser drives Chromium profiles over CDP through Puppeteer, and sets values such as the user agent, Client Hints, language, time zone and geolocation on every page, popup and worker as it starts. Each profile gets a fixed DevTools port. The local API’s start request returns the profile’s `wsEndpoint` so your own Puppeteer code can attach. From version 1.0.22, SoftGlaze AI (Beta) adds an Expert tool, off by default, that hands a running profile’s endpoint to Playwright, Puppeteer or Chrome DevTools, with a warning that an outside debugger is detectable and an approval every time.

### Sources

1.  [Chrome DevTools Protocol](https://chromedevtools.github.io/devtools-protocol/) Google (GitHub)
2.  [Puppeteer: connect to an existing browser](https://pptr.dev/api/puppeteer.puppeteer.connect) Puppeteer

Outside sources were checked in November 2026. Browsers, standards and vendors' pages change, so details that depend on them are as of that month.

### Related terms

-   [Puppeteer](https://browser.softglaze.com/glossary/puppeteer) Puppeteer is an open-source JavaScript library from Google's Chrome team for controlling Chrome or Firefox from code, through the Chrome DevTools Protocol or WebDriver BiDi.
-   [Playwright](https://browser.softglaze.com/glossary/playwright) Playwright is an open-source browser automation library from Microsoft that controls Chromium, Firefox and WebKit from one API, available for JavaScript, Python, Java and .NET.
-   [Browser automation](https://browser.softglaze.com/glossary/browser-automation) Browser automation is software controlling a web browser the way a person would, opening pages, clicking, typing and reading results, either from code, from a recorded macro or from an AI app.
-   [navigator.webdriver](https://browser.softglaze.com/glossary/navigator-webdriver) navigator.webdriver is a browser property that the W3C WebDriver standard requires to be true when the browser is under automated control, so a page can tell an automated session from a person using the browser.
-   [Headless browser](https://browser.softglaze.com/glossary/headless-browser) A headless browser is a web browser running without a visible window, controlled by a program, which loads and runs pages exactly as a normal browser would but shows nothing on screen.

### Read more on this site

-   [Docs: local API](https://browser.softglaze.com/docs/automation#local-api)
-   [Docs: AI tools, Expert (get\_cdp\_endpoint)](https://browser.softglaze.com/docs/ai-tools#expert)
-   [Automation: local API](https://browser.softglaze.com/features/automation#local-api)

### See it in SoftGlaze Browser

Separate profiles, each with its own cookies, device values and proxy, on Windows. Try the app's screens in your browser first, or start the free trial; no card needed.

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