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Adquire the plugin in UE4 Marketplace!

C++ Hot Reload for Unreal Engine 4

C++ Hot Reload is a plugin that allows the Unreal Editor to detect modified classes and build them automatically in background allowing you to modify the headers files and the classes structures for Windows and macOS. C++ Hot Reload will only build the modified files to speed up your work in large projects or plugins.

You know the plugin is installed when you see in your tool bar the following similar image Image of Status button



  • UE4.23, UE4.24 and UE4.25
  • Reload header files
  • No matter how big is your project, you'll reload only the modified files
  • Supports macOS and Windows using 64bits
  • PCH based for fast reload, even .h files changing the classes layouts it's able to reload in the gap of seconds
  • See how to speed up macOS builds (~40%) in the section below


  1. Install the plugin using the UE marketplace
  2. The plugin will auto-configure it self with your target project
  3. Recommendation: deactivate Edit and Continue in Visual Studio:

Understanding the status bar

  • Image of waiting Waiting for the user save a file
  • Image of UE Header tool running Unreal Header Tool is running (when you modify a .h file)
  • Image of NO PCH You have no PCH file configured for your project and files, the reload will be much slower
  • Image of Building Building!

Feedback and Help

Image of Discord

For any other question: contact AT or file an issue here in GitHub


Test projects

UE4 classes tested here

Enter in the Discord channel and send your sample class to get support!

  • ActorComponent
  • SceneComponent

1000 simple components

Test machine for Win64: Corei7-4790 3.6 GHz, 3601 Mhz, 4 Cores - SSD 860 EVO Test machine for macOS: MBP 2018, Corei7 2.6 Ghz, 6 Cores - SSD Located in:

// Test "1000 simple components", without dependencies or dependents

// Modifying a CPP file
1st change, Win64: UE4 11.5s vs 3.0s | macOS: 35.2s vs 9.0s
2nd change, Win64: UE4 10.5s vs 3.3s | macOS: 50.9s vs 8.6s
3rd change, Win64: UE4 12.5s vs 3.1s | macOS: 45.3s vs 8.3s

// Modifying a H file. + correspond to Unreal Header Tool
1st change, Win64: UE4 45.6s vs 3.3s + 29s | macOS: 102.9s vs  9.2s + 10s
2nd change, Win64: UE4 22.4s vs 3.5s + 10s | macOS:  70.3s vs  9.9s + 9s
3rd change, Win64: UE4 22.0s vs 3.4s + 7s  | macOS:  65.9s vs 10.2s + 9s


About macOS

  • If you need to generate debug symbols to better inspection, go to the file CppHotReloadConfig.h and set CPP_HOT_RELOAD_SPEED_UP_ON_MACOS to 0