UE4SS

Free#6 of 26 in Game Mod Loaders

UE4SS: A deep Unreal Engine mod loader for Windows modders and developers. Ranked #6 of 26 in Game Mod Loaders by our editors (8.4/10); pricing: Open source; best for unreal Engine game modding.

8.4/10★★★★☆Editor score

Visit UE4SS

UE4SS8.4 Visit UE4SS

At a glance

• Editor score
  8.4 / 10
• Pricing
  Open source
• Best for
  Unreal Engine game modding
• Paid from
  Free
• Facts checked
  20 Sep 2026

• Where it wins

  • Lua and C++ APIs support script-based and native mods
  • Blueprint loading, actor spawning, and live property editing
  • Automatic or manual injection with configurable mod ordering

• Where it doesn't

  • Windows is the published supported platform
  • Injection requires installation alongside a game executable
  • The broad Unreal Engine scope may require game-specific compatibility checks

Our verdict on UE4SS

UE4SS is an open-source modding system for Unreal Engine 4 and 5 games, aimed at players and developers who want to load, create, or debug mods on Windows. It injects into supported game processes and combines Lua scripting with a C++ modding API. Blueprint mod loading, actor spawning, live property editing, SDK and header dumping, and mod configuration give it a wide set of tools for Unreal Engine mod work.

Its strongest area is development depth. The Lua API can interact with Unreal Engine objects, while the C++ API supports native game modifications. Unreal Header Tool-compatible header generation and C++ header dumping expose reflected classes, blueprints, and offsets for more advanced projects. The live property viewer and editor also support runtime inspection and changes. Mods can be enabled and ordered through mods.txt, and users can choose a basic end-user build or a developer build with additional debugging and dumping tools.

Installation follows an injection-based model: UE4SS is installed alongside a game executable, with automatic or manual DLL injection available. That approach fits users comfortable with game files, configuration, and mod-development workflows more than newcomers looking for a standalone mod manager. Windows is the supported platform in the published build and installation documentation, while Linux support is described as future work. Choose UE4SS for broad Unreal Engine modding capabilities, scripting, native extensions, and development utilities; consider an alternative if you need another operating system or prefer a loader that does not rely on process injection.

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UE4SS pricing

UE4SS fact sheet

Alternatives to UE4SS

• MMelonLoaderA flexible Unity mod loader with plugins, dependencies, debugging, and cross-platform support.9.4
• BBepInExA free, open-source loader for multi-framework desktop game modding.9.2
• SMAPIA capable, free loader for Stardew Valley mods, diagnostics, dependencies, and save backups.8.9

See all UE4SS alternatives →

UE4SS vs the competition

• MUE4SS vs MelonLoader
• BUE4SS vs BepInEx
• UE4SS vs SMAPI
• UE4SS vs Northstar
• UE4SS vs Everest
• SMUE4SS vs Satisfactory Mod Loader

Compare UE4SS with any tool side by side →

Featured on iTechGuides

UE4SS is listed in our Game Mod Loaders directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update