explaingit

justjavac/replacegooglecdn

Analysis updated 2026-05-18

3,650JavaScriptAudience · generalComplexity · 1/5Setup · easy

TLDR

ReplaceGoogleCDN is a browser extension that redirects blocked Google-hosted web resources to faster mirrors for users in China.

Mindmap

mindmap
  root((ReplaceGoogleCDN))
    What it does
      Redirects blocked requests
      Swaps CDN domains
      Speeds up page loads
      Toggleable rules
    Tech stack
      JavaScript
      Chrome extension APIs
      WebRequest and declarativeNetRequest
    Use cases
      Fix broken pages in China
      Speed up jQuery and Bootstrap loading
      Load Google Fonts from a mirror
    Audience
      General users
      Web developers in China

Code map

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filefunction / class

What do people build with it?

USE CASE 1

Stop websites from hanging while waiting on blocked Google CDN resources.

USE CASE 2

Speed up loading of common libraries like jQuery and Bootstrap in China.

USE CASE 3

Redirect Google Fonts requests to a working mirror automatically.

USE CASE 4

Toggle which specific CDN domains get redirected through a settings page.

What is it built with?

JavaScriptChrome Extension API

How does it compare?

justjavac/replacegooglecdnwonderunit/storyboarderpanphora/overtype
Stars3,6503,6493,652
LanguageJavaScriptJavaScriptJavaScript
Setup difficultyeasyeasyeasy
Complexity1/51/52/5
Audiencegeneralgeneraldeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

README is written in Chinese.

Not stated in the provided README excerpt.

In plain English

ReplaceGoogleCDN is a browser extension for Chrome, Firefox, and Edge that automatically redirects requests for Google-hosted web resources to alternative servers located in China. The problem it solves is specific to internet users in China: many websites load JavaScript libraries, fonts, and other assets from Google's content delivery network, but those Google servers are blocked in China, which means pages either load very slowly or break entirely while waiting for resources that will never arrive. The extension works by intercepting network requests in the browser before they go out, and swapping the destination address. For example, a request to Google's font service gets redirected to a Chinese mirror of the same fonts. A JavaScript library that a site loads from Google gets fetched from a faster domestic server instead. The extension handles around 16 different Google-served resources including common libraries like jQuery and Bootstrap, the reCAPTCHA verification widget, Google Fonts, and developer documentation sites. Most of the redirects are turned on by default. A few optional ones, like redirecting jsDelivr or cdnjs, can be toggled through the extension's settings page, which you open by double-clicking the extension icon. The README is written in Chinese and includes a performance comparison showing the before-and-after load times for various resources on a site like Stack Overflow. In one example, a jQuery file that stalled completely from the Google server loaded in 95 milliseconds from the replacement server. The extension is available in the Chrome Web Store, Firefox Add-ons, and the Edge Add-ons store. It can also be installed manually from source by loading it as an unpacked developer extension.

Copy-paste prompts

Prompt 1
Show me how to install ReplaceGoogleCDN from the Chrome Web Store.
Prompt 2
Help me manually load this extension as an unpacked extension in developer mode.
Prompt 3
Explain which Google CDN domains this extension redirects by default.
Prompt 4
Walk me through toggling an optional redirect rule in the extension's settings page.

Frequently asked questions

What is replacegooglecdn?

ReplaceGoogleCDN is a browser extension that redirects blocked Google-hosted web resources to faster mirrors for users in China.

What language is replacegooglecdn written in?

Mainly JavaScript. The stack also includes JavaScript, Chrome Extension API.

What license does replacegooglecdn use?

Not stated in the provided README excerpt.

How hard is replacegooglecdn to set up?

Setup difficulty is rated easy, with roughly 5min to a first successful run.

Who is replacegooglecdn for?

Mainly general.

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