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SPECIFICTION
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Baldur's Gate 3 Script Extender

github.com

Free plan Open source WindowsLinuxAPI
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Spec score 8.9 #2 of 26 in Game Mod Loaders

What it is

Baldur's Gate 3 Script Extender adds Lua and Osiris scripting support for mods in Baldur's Gate 3. A mod can enable Lua with a feature flag and load bootstrap scripts for the client and server. The extender keeps separate Lua states for the game server and each client, and its console can run Lua code and registered console commands. Configuration options provide Lua and Osiris debugger interfaces with configurable listening ports, and logging options can write Osiris activity, runtime output, story compilation and compilation errors to files. An EnableAchievements option can re-enable achievements in modded games. SendCrashReports defaults to true and uploads minidumps to a crash report collection server after a crash. Installation involves extracting DWrite.dll into the game's bin directory. The extender updates when the game launches by downloading and applying an update. It supports Windows and Linux via Proton, but does not run on game versions older than patch 5; new versions target the latest game version. It is free to obtain under a license that includes the MIT License and a Commons Clause restriction on selling the software or substantially derived products and services.

Spec sheet

What it does
Adds Lua and Osiris scripting support to Baldur's Gate 3 for mods.Read 15 Oct 2026 · github.com
Purpose
The Script Extender adds Lua and Osiris scripting support to Baldur's Gate 3.Read 8 Oct 2026 · github.com
Intended users
The documentation describes using the extender in mods, including setting a mod configuration file and Lua feature flag.Read 8 Oct 2026 · github.com
License
The repository license includes the MIT License and a Commons Clause condition that excludes selling the software or substantially derived products and services.Read 8 Oct 2026 · github.com
Achievements
The default configuration re-enables achievements for modded games.Read 15 Oct 2026 · github.com
Automatic updates
The updater downloads and applies the matching extender when the game launches, so GitHub releases represent updater changes rather than every extender build.Read 15 Oct 2026 · github.com
Build requirements
Developers are instructed to run first-time-setup.bat from an MSVC x64 Native Tools command prompt and then use Visual Studio.Read 15 Oct 2026 · github.com
Client and server
The extender maintains separate Lua states for the game server and each client.Read 8 Oct 2026 · github.com
Console
The extender provides an interactive console that executes Lua and can invoke Osiris functions.Read 15 Oct 2026 · github.com
Console limitation
The community installation guide says PlayStation and Xbox have no official Script Extender support.Read 15 Oct 2026 · wiki.bg3.community
Crash reports
The SendCrashReports option defaults to true and uploads minidumps to a crash report collection server after a game crash.Read 8 Oct 2026 · github.com
Debugger ports
The documented default ports are 9999 for Osiris debugging and 9998 for Lua debugging.Read 15 Oct 2026 · github.com
Debugging
Configuration supports console logging, runtime logs, compilation logs, an Osiris debugger and a Lua debugger.Read 15 Oct 2026 · github.com
Documentation depth
The Lua API document is about 1,957 lines and includes examples and function behavior details.Read 15 Oct 2026 · github.com
Events API
Lua scripts can subscribe to engine events with priority and one-shot options.Read 15 Oct 2026 · github.com
Game data APIs
Documented modules cover entities, stats, resources, localization, audio, templates, level operations and math.Read 15 Oct 2026 · github.com
Game version limit
The FAQ says the extender does not run on game versions older than patch 5 and new versions are released for the latest game version.Read 8 Oct 2026 · github.com
Independent installation support
BG3 Wiki says the extender can be installed manually or through Baldur's Gate 3 Mod Manager and updates itself at game startup.Read 15 Oct 2026 · bg3.wiki
Independent praise: ecosystem importance
A BG3 modding guide presents the extender as the foundation for writing mods with Lua and Osiris scripting.Read 15 Oct 2026 · wiki.bg3.community
Independent praise: mod compatibility
PC Gamer describes the extender as Patch 8 verified and often required for many other Baldur's Gate 3 mods.Read 15 Oct 2026 · pcgamer.com
Installation
The official release instructs users to extract DWrite.dll into the game's bin directory.Read 15 Oct 2026 · github.com
Licence
The repository combines an MIT licence with a Commons Clause condition that excludes selling the software or services whose value substantially derives from it.Read 15 Oct 2026 · github.com
Limit: crash causes
The official troubleshooting guide says crashes commonly result from game-version incompatibility or incompatible mods after a game update.Read 15 Oct 2026 · github.com
Limit: update breakage
A Reddit discussion reports that automatic updating to version 33 produced an error and users needed developer mode to select version 32.Read 15 Oct 2026 · reddit.com
Linux support
The community installation guide documents Windows and Linux/Steam Deck use through Proton, with extra launch options required.Read 15 Oct 2026 · wiki.bg3.community
Logging
Configuration options can log Osiris activity, runtime output, story compilation, and compilation errors to files.Read 8 Oct 2026 · github.com
Lua scripting
Mods can load separate client and server Lua bootstrap scripts.Read 15 Oct 2026 · github.com
Mac limitation
The community installation guide says macOS has no official Script Extender support.Read 15 Oct 2026 · wiki.bg3.community
Mod scripting
Mods can enable Lua through a feature flag and load client and server bootstrap scripts.Read 8 Oct 2026 · github.com
Networking
The API includes a NetChannel networking interface and related utilities.Read 15 Oct 2026 · github.com
Nexus integration
The Nexus page says its copy is identical to GitHub's version and supports installation through Vortex or manual DLL extraction.Read 15 Oct 2026 · nexusmods.com
Nexus listing
Nexus lists version v33-20261012, marks it safe to use, and identifies Norbyte as creator and uploader.Read 15 Oct 2026 · nexusmods.com
Notable news
Norbyte published Script Extender version 33 on 12 October 2026.Read 15 Oct 2026 · github.com
Osiris integration
Lua server contexts expose the game's Osiris calls, queries, events and databases.Read 15 Oct 2026 · github.com
Patch support
The latest release states that Patch 8 is supported and versions older than Patch 5 are unsupported.Read 15 Oct 2026 · github.com
Persistence
The API documents user variables, mod variables, synchronization and caching behavior.Read 15 Oct 2026 · github.com
Repository activity
The public repository shows about 1.5k stars, 118 forks, 207 issues and 13 pull requests.Read 15 Oct 2026 · github.com
UI extensibility
The API documents Noesis UI access, custom view models, input handling and world interaction.Read 15 Oct 2026 · github.com
Updates
The release FAQ says the extender auto-updates when the game launches and downloads and applies an update.Read 8 Oct 2026 · github.com
Version matching
The extender targets a specific game build; an extender built for Patch 8 does not work with Patch 7.Read 15 Oct 2026 · nexusmods.com
Warranty
The license provides the software as is and disclaims warranties including merchantability and fitness for a particular purpose.Read 8 Oct 2026 · github.com

Plans and prices

Baldur's Gate 3 Script Extender Free Free to obtain under the published license; Commons Clause restricts selling software whose value substantially derives from it Read 8 Oct 2026 · github.com
Baldur's Gate 3 Script Extender Free Windows/Linux Proton modding tool · requires Baldur's Gate 3 · version-specific compatibility Read 15 Oct 2026 · github.com

Every Baldur's Gate 3 Script Extender plan and price →

Strong points and limits

Strong points

  • Adds Lua and Osiris scripting support for mods.
  • Includes a console for Lua code and commands.
  • Offers debugger and logging configuration options.
  • Can update when the game launches.
  • Free to obtain under its published license.

Limits

  • Does not run on game versions older than patch 5.
  • New releases target the latest game version.
  • Crash-report uploads are enabled by default.
  • Commons Clause restricts selling the software and substantially derived products.

Who it suits

The Script Extender is for Baldur's Gate 3 mod creators who want Lua or Osiris scripting support and related debugging or logging options. It requires game patch 5 or later and supports Windows and Linux via Proton.

Verdict

The extender supplies scripting, console, debugging and logging tools for Baldur's Gate 3 mods. Check the game's version requirement and license condition, and note that crash-report uploads are enabled by default.

Where Specifiction places it

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