Who Raddebugger is for#
Debugging large game engines and native applications
Teams working on game engines or other large C/C++ projects where PDB files exceed gigabytes and link times dominate the iteration cycle. The RAD Linker's 50% faster link times and the RDI format's optimized loading directly reduce the wait between code change and debug session.
Skip if:
Your project is small enough that standard linker and debugger performance is not a bottleneck.
Replacing per-seat debugger licenses
Organizations using commercial debuggers like RemedyBG across multiple developer seats. RAD Debugger provides a comparable native debugging experience under the MIT license with no per-seat cost, making it practical for teams scaling from a few developers to dozens.
Skip if:
You need Linux-native debugging today, since that support is still under development.
Standalone debugging without an IDE
Developers who prefer lightweight, terminal-driven workflows and do not want to run a full IDE for debugging. RAD Debugger operates independently, needs only MSVC or Clang build tools, and produces a single executable.
Skip if:
You rely heavily on IDE-integrated debugging features like inline variable watches tied to your editor.
The problem it solves#
Native application debugging on Windows typically requires either a full IDE like Visual Studio or a paid tool like RemedyBG. Both options create friction: IDEs bundle far more than a debugger, and commercial tools charge per seat. For large codebases, the bigger pain is the debug cycle itself. PDB files can grow to multiple gigabytes, making debug info loading slow, and standard linkers become the bottleneck during iteration. Developers working on game engines, operating systems, or other large native projects spend significant time waiting for builds to link and debuggers to load symbols.
How it solves it#
Multi-process graphical debugging
Debug multiple processes simultaneously through a native graphical interface. The debugger runs entirely in user mode and currently supports local-machine Windows x64 debugging with PDB files, with Linux support actively under development.
RAD Debug Info (RDI) format
A custom debug information format optimized for fast parsing. The debugger converts PDB (and eventually DWARF) into RDI on-demand, and the included radbin utility can also pre-convert and dump RDI contents. The format specification lives in code under src/lib_rdi.
Performance linker for large executables
The RAD Linker generates x64 PE/COFF binaries with standard PDB output and optional native RDI generation. Benchmarked at 50% faster link times on projects with multi-gigabyte debug info. Supports large memory pages for an additional 25% reduction in link time.
MSVC-compatible command line
The RAD Linker uses command line syntax fully compatible with MSVC, making it a drop-in replacement for existing build systems. Run /help to see the full list of implemented switches.
Cross-platform build system
Builds on Windows with MSVC or Clang via build.bat, and on Linux with GCC or Clang via build.sh. Both debug and release configurations are supported with a single argument.
Strengths and trade-offs#
Strengths
- Speed on large projectsThe combination of the RDI format and the performance linker specifically targets the pain of debugging huge executables. Where standard toolchains produce broken PDBs that overflow internal 32-bit tables, the RAD Linker and RDI format handle multi-gigabyte debug info cleanly.
- Backed by Epic GamesDeveloped and maintained by Epic Games under the MIT license. The project has 7,800+ stars, 383 forks, and active development with the most recent push on October 7, 2026. The backing provides confidence in long-term maintenance for a tool that developers integrate into their daily workflow.
- Standalone and focusedUnlike IDE-embedded debuggers, RAD Debugger is a single-purpose tool. It does not require Visual Studio, an IDE subscription, or any runtime beyond the build tools needed to compile it.
Trade-offs
- -Alpha status with known gapsThe debugger is currently in alpha. There are 311 open issues on GitHub, and the team actively solicits bug reports including dump files and reproduction steps. Users should expect occasional rough edges.
- -Limited platform support todayCurrently only supports local-machine Windows x64 debugging with PDBs. Linux debugging and DWARF support are on the roadmap but not yet complete. Developers on Linux can build the project but cannot use it as their primary debugger yet.
- -No link-time optimizations yetThe RAD Linker does not yet support dead-code elimination (/opt:ref) or link-time optimizations. These features are planned but not available, which means the linker is best suited for debug builds during the compile-debug cycle rather than final release builds.
Raddebugger vs alternatives#
RAD Debugger vs RemedyBG
RemedyBG is a commercial Windows debugger known for its speed, minimal memory footprint, and fast startup. It focuses on being a lightweight, high-performance debugging tool for C/C++ developers who find Visual Studio's debugger too slow or bloated.
RAD Debugger targets the same audience but takes a broader approach. Beyond the debugger itself, the project includes the RDI debug info format and the RAD Linker, addressing the full compile-debug cycle rather than just the debugging step. For large projects, the linker's 50% faster link times and native RDI generation remove bottlenecks that RemedyBG cannot address since it operates only on the debugging side.
RemedyBG requires a paid license. RAD Debugger is MIT-licensed and maintained by Epic Games, making it free for any team size. RemedyBG is more mature as a debugger (RAD Debugger is still in alpha), but RAD Debugger's scope is wider and its open source nature means any developer can inspect, modify, or contribute to the codebase.
For developers who need a fast debugger today on Windows with minimal setup, RemedyBG is the more polished option. For teams working on large native projects who want an open source toolchain that covers linking, debug info, and debugging in one package, RAD Debugger is the stronger fit.
Quick start#
Install by cloning the repository and running the build script locally.
```bash
git clone https://github.com/EpicGames/raddebugger.git
cd raddebugger
./build.sh release
```What it's built on#
- Languages
- CC++
FAQ#
What platforms does RAD Debugger support?
RAD Debugger currently supports local-machine Windows x64 debugging with PDB debug information. Linux x64 debugging with DWARF support is on the roadmap and actively being developed. The project builds on both Windows (MSVC or Clang) and Linux (GCC or Clang), but the debugger's process control and debug info features are currently Windows-only.
How does the RAD Linker compare to the MSVC linker?
On large projects with multi-gigabyte debug information, the RAD Linker benchmarks at 50% faster link times. It uses MSVC-compatible command line syntax, so it works as a drop-in replacement. Enabling large memory pages via /rad_large_pages provides an additional 25% improvement, though large pages are recommended only in Docker or VM environments on Windows due to memory fragmentation issues.
Is RAD Debugger free to use commercially?
Yes. RAD Debugger is released under the MIT license, which permits commercial use, modification, and distribution without restrictions or per-seat fees.
What is the RDI format and why does it exist?
RAD Debug Info (RDI) is a custom debug information format designed for faster parsing and querying than PDB or DWARF. The debugger converts existing debug info to RDI on-demand. The RAD Linker can also generate RDI natively alongside standard PDB output, which eliminates conversion overhead and handles executables too large for PDB's internal 32-bit tables.
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