Remote network and data debugging for your native iOS app using Chrome Developer Tools
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PonyDebugger Logo


PonyDebugger is a remote debugging toolset. It is a client library and gateway server combination that uses Chrome Developer Tools on your browser to debug your application's network traffic and managed object contexts.

To use PonyDebugger, you must implement the client in your application and connect it to the gateway server. There is currently an iOS client and the gateway server.

PonyDebugger is licensed under the Apache Licence, Version 2.0 (


Network Traffic Debugging

PonyDebugger sends your application's network traffic through ponyd, PonyDebugger's proxy server. You use Inspector's Network tools to debug network traffic like how you would debug network traffic on a website in Google Chrome.

PonyDebugger Network Debugging Screenshot

PonyDebugger forwards network traffic, and does not sniff network traffic. This means that traffic sent over a secure protocol (https) is debuggable.

Currently, the iOS client automatically proxies data that is sent via NSURLConnection. This means that it will automatically work with AFNetworking, and other libraries that use NSURLConnection for network requests.

Core Data Browser

The Core Data browsing feature allows you to register your applcation's NSManagedObjectContexts and browse all of its entities and managed objects. You browse data from the IndexedDB section in the Resource tab in Chrome Developer Tools.

PonyDebugger Core Data Browser Screenshot

These are read-only stores at the moment. There are plans to implement data mutation in a future release.

Quick Start

Prerequisite: Xcode's Command Line Tools must be installed from the "Downloads" preference pane.

curl -sk | \
  python - --ponyd-symlink=/usr/local/bin/ponyd ~/Library/PonyDebugger

This will install ponyd script to ~/Library/PonyDebugger/bin/ponyd and attempt to symlink /usr/local/bin/ponyd to it. It will also download the latest chrome dev tools source.

Then start the PonyDebugger gateway server

ponyd serve --listen-interface=

In your browser, navigate to http://localhost:9000. You should see the PonyGateway lobby. Now you need to integrate the client to your application.

For more detailed instructions, check out the gateway server README_ponyd.

PonyDebugger iOS Client

The PonyDebugger iOS client lets you to debug your application's network requests and track your managed object contexts.


  • Requires iOS 5.0 or above
  • Uses ARC (Automatic Reference Counting).
  • Uses SocketRocket as a WebSocket client.


  • Extract a tarball or zipball of the repository into your project directory. If you prefer, you may also add the project as a submodule. The iOS client uses SocketRocket as a dependency, and it is included as a submodule.
cd /path/to/YourApplication
mkdir Frameworks
git submodule add git:// Frameworks/PonyDebugger
git submodule update --init --recursive
  • Add PonyDebugger/PonyDebugger.xcodeproj as a subproject.

PonyDebugger Installing Subproject

  • In your Project Settings, add the PonyDebugger target as a Target Dependency in the Build Phases tab.

PonyDebugger Installing Target Dependencies

  • Link libPonyDebugger.a, libSocketRocket.a, and the Framework dependencies to your project.

PonyDebugger Installing Link Libraries and Frameworks

  • In your project's Build Settings, add "$(CONFIGURATION_BUILD_DIR)/usr/local/include"(with quotes) as a non-recursive Header Search Path.

PonyDebugger Installing Header Search Path

  • PonyDebugger and SocketRocket take advantage of Objective C's ability to add categories on an object, but this isn't enabled for static libraries by default. To enable this, add the -ObjC flag to the "Other Linker Flags" build setting.

PonyDebugger Installing Other Linker Flags

Framework Dependencies

Your .app must be linked against the following frameworks/dylibs in addition to libPonyDebugger.a and libSocketRocket.a.

  • libicucore.dylib
  • CFNetwork.framework
  • CoreData.framework
  • Security.framework
  • Foundation.framework


PonyDebugger's main entry points exist in the PDDebugger singleton.

PDDebugger *debugger = [PDDebugger defaultInstance];

To open the connection to ws://localhost:9000/device:

[debugger connectToURL:[NSURL URLWithString:@"ws://localhost:9000/device"]];

To manually close the connection:

[debugger disconnect];

Network Traffic Debugging

To enable network debugging:

[debugger enableNetworkTrafficDebugging];

PonyDebugger inspects network data by injecting logic into NSURLConnectionDelegate classes. If you want PonyDebugger to automatically find these classes for you:

[debugger forwardAllNetworkTraffic];

This will swizzle methods from private APIs, so you should ensure that this only gets invoked in debug builds. To manually specify delegate classes:

[debugger forwardNetworkTrafficFromDelegateClass:[MyClass class]];

These methods should be invoked before the connection is opened.

Core Data Browser

PonyDebugger also allows you to browse your application's managed objects. First, enable Core Data debugging:

[debugger enableCoreDataDebugging];

To register a managed object context:

[debugger addManagedObjectContext:self.managedObjectContext withName:@"My MOC"];

The repository contains a test application to demonstrate PonyDebugger's capabilities and usage.

Known Issues / Improvements

  • CoreData.framework must be linked, even if you do not use the Core Data browsing functionality.
  • iOS 5.1 and below: In certain cases, -[NSURLConnectionDataDelegate connection:willSendRequest:redirectResponse:] will never get called. PonyDebugger requires this call to know when the request was sent, and will warn you with a workaround that the timestamp is inaccurate.

    To fix the timestamp, make sure that Accept-Encoding HTTP header in your NSURLRequest is not set (by default, iOS will set it to gzip, deflate, which is usually adequate.

    AFNetworking users: if you subclass AFHTTPClient, call [self setDefaultHeader:@"Accept-Encoding" value:nil];.


Any contributors to the master PonyDebugger repository must sign the Individual Contributor License Agreement (CLA). It's a short form that covers our bases and makes sure you're eligible to contribute.

When you have a change you'd like to see in the master repository, send a pull request. Before we merge your request, we'll make sure you're in the list of people who have signed a CLA.

Some useful links: