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uProxy is a browser extension that lets users share their internet connection.


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Please read the uProxy Coding Guide to learn more about contributing to uProxy. For a high level technical overview of uProxy, see the uProxy Design Doc.


uProxy is built using the following tools:

  • Grunt to write the tasks that build uProxy
  • TypeScript as the primary language we code in; this compiles to JavaScript. It gives us type-checking and has some syntax improvements on JS, while letting us incrementally migrate and easily include external JS packages and frameworks.
  • Jasmine for testing
  • Polymer for UI
  • Travis for continuous integration

To manage dependencies we use:

  • npm to install node modules that we use for our build process. (Specified in package.json)
  • Bower to install libraries that we use in the UI (specified in bower.json) including Polymer.



  • Yarn. If you have npm, you can install with npm install -g --production yarn.
  • grunt-cli (once you've installed NPM, simply execute yarn global add --prod grunt-cli)


First, to install required NPMs and configure the build/ directory for TypeScript compilation, execute:


Then, to compile the TypeScript code and build uProxy and all of the demo apps, execute:


Having problems? To clean up from a partial, broken, or extremely out-dated build, try executing this command before repeating the above steps:

yarn run clean


Visual Studio Code supports TypeScript compilation, search, and refactoring out of the box - just point it at the directory containing your uProxy clone.




These are the steps to try uProxy in the Chrome browser.

  • In Chrome, go to chrome://extensions, make sure 'Developer mode' is enabled
  • Click 'Load unpacked extension...' and select build/src/chrome/app
  • Click 'Load unpacked extension...' and select build/src/chrome/extension

You need both the uProxy Chrome App and the uProxy Extension.

You can use grunt build_chrome from the root directory of the repository to re-compile just Chrome components.


These are the steps to try uProxy in the Firefox browser.

  • To run the add-on you need to have the Firefox add-on SDK installed. Instructions can be found here:

    • A quick way to get started is to download/extract the zip mentioned in "Prerequisites"
  • Run cd build/src/firefox

  • Run cfx run and Firefox should launch with the uProxy add-on installed

You can use grunt build_firefox from the root directory of the repository to compile just Firefox comonents.

Demo apps

These can be found at build/src/samples/. They are a mix of web sites, browser extensions (Chrome and Firefox), and Node.js apps.

To run web apps:

To run Chrome apps:

  • open chrome://extensions, enable check Developer Mode, and load the unpacked extension from the relevant directory, e.g. build/src/samples/simple-socks-chromeapp/.

To run Firefox add-ons:

  • install jpm via NPM, e.g. yarn install jpm -g, cd to the relevant directory, e.g. build/src/samples/simple-socks-firefoxapp/, and execute jpm run -b `which firefox` .

To run Node.js apps:

  • Directly run node with the entry point, e.g. node build/src/samples/zork-node/index.js

Note: until freedom-for-node supports core.rtcpeerconnection, this sample will not work

More on the demo apps themselves:

  • simple-freedom-chat is a WebRTC-powered chat client, with both peers on the same page. This is the simplest possible demo src/peerconnection.
  • copypaste-freedom-chat is the simplest possible, distributed, src/peerconnection demo in which text boxes act as the signalling channel between two peers. Messages can be exchanged by email, IM, shared doc, etc.
  • echo-server starts a TCP echo server on port 9998. Run telnet 9998 and then type some stuff to verify that echo server echoes what you send it. Press ctrl-D to have the echo server terminate the connection or press ctrl-] then type quit to exit telnet.
  • Simple SOCKS is the simplest possible, single-page, demo of the SOCKS proxy (socks-to-rtc and rtc-to-net directories). This command may be used to test the proxy: curl -x socks5h://localhost:9999 (-h indicates that DNS requests are made through the proxy too)
  • Zork is a distributed SOCKS proxy with a telnet-based signalling channel, intended for use with our Docker-based integration testing. Try connecting to Zork with telnet localhost 9000.
  • uProbe guess-timates your NAT type.
  • simple-churn-chat is just like simple-freedom-chat, except WebRTC traffic between the two peers is obfuscated. Wireshark may be used to verify that the traffic is obfuscated; the endpoints in use - along with a lot of debugging information - may be determined by examining the Javascript console.
  • copypaste-freedom-chat is just like copypaste-fredom-chat, except WebRTC traffic between the two peers is obfuscated.

Development and re-building uProxy

uProxy uses the Grunt build system for its build tasks. Here is a list of uProxy's Grunt commands:

  • build - Builds everything, making stuff in the build directory (and runs tests).
  • build_chrome - Build Chrome app and extension * build_chrome_app - Build just Chrome app * build_chrome_ext - Build just Chrome extension
  • build_firefox - Build just Firefox
  • dist - Generates distribution files, including the Firefox xpi
  • clean - Cleans up
  • test - Run unit tests
  • integration_test - Run integration tests
  • everything - 'build', 'test' and then 'integration_test'

The easiest way to stay current is to pull changes, run grunt build to build your distribution, and re-run as you make changes to the files.

Before submitting any changes to the repository, make sure to run grunt test to make sure it passes all unit tests. Failing tests are enough to immediately reject submissions. :)

uProxy for Mobile

The development for mobile platforms uses the Cordova Chrome Apps (CCA) tool, also known as the Chrome Apps for Mobile Toolchain. You can find the platform-specific information below:

Layout of files

Configuration and setup files

  • Gruntfile.js a file that specifies common tasks, e.g. how to build and package uProxy.
  • bower.json specifies dependent libraries from Bower.
  • package.json specifies dependent libraries from NPM.
  • .gitignore what git should ignore
  • .bowerrc tells bower where to put files
  • .travis.yml Travis auto-testing
  • tools directory contains some typescript and javascript to help Grunt.
  • third_party/tsd.json specifies the typescript definitions to use

Source code

  • src holds all source code; no compiled files
  • src/generic_ui generic user interface code
  • src/generic_core generic uproxy core-functionality code
  • src/chrome/app code specific to the chrome app
  • src/chrome/extension code specific to the chrome extension
  • src/firefox code specific to firefox
  • third_party holds external libraries we depend on that are copied into this repository
  • node_modules dynamically generated npm module dependencies
  • scraps temporary holding for sharing scraps of code

Dynamically created directories (grunt clean should remove them)

  • build created by grunt tasks; holds the built code, but none of the code that was compiled.
  • build/dist created by grunt tasks; holds final distribution versions
  • .grunt holds grunt cache stuff
  • .tscache holds typescript cache stuff