BepInEx vs Fallout 4 Script Extender (F4SE)

BepInEx is a plugin and modding framework for Unity Mono and IL2CPP games, as well as .NET Framework games such as those built with XNA, FNA, and MonoGame. It provides configuration and logging, runtime method patching, and in-memory assembly patching. Runtime patching uses Harmony, including HarmonyX and MonoMod; in-memory patching uses Mono.Cecil with UnityDoorstop. The installation guide lists Windows, Linux, and macOS, though supported operating system versions and architectures depend on the build and game. Setup is manual: download the appropriate build and put its contents in the game’s root folder. Official binaries are available as stable and bleeding edge builds; the documentation recommends stable in most cases and notes that bleeding edge builds tend to be buggier. The project is open source under LGPL-2.1 and links to guides for users and developers. Compatibility has limits: stable releases are available only for Unity Mono, BepInEx 6 documentation remains a work in progress, and BepInEx 5 plugins do not yet work with the 6.0.0 pre-release.

Fallout 4 Script Extender (F4SE) is a free Windows resource for Fallout 4 modders who need expanded scripting capabilities. It extends scripting without changing the game’s executable files on disk. Listed interfaces include the Papyrus plugin API and hooks for Papyrus, Scaleform, and the classic script system. The homepage lists build 0.7.9 for Fallout 4 runtime 1.11.240. F4SE supports Fallout 4 releases from Steam and GOG, while MS Store, Game Pass, Epic, and other Windows Store versions are unsupported because those applications do not provide required APIs. Native code plugins require updates from their creators for runtime 1.10.980 and later, and plugins must have publicly available source code. Injection loads mods and may trigger poorly written virus scanners. Additional utilities include a command-line BA2 archive extractor and PEX script disassembler. The project is provided as-is and directs installation questions to its subreddit.