Open-source alternatives to TModLoader

Veloren is an open-source multiplayer RPG featuring a voxel-based action adventure in a procedurally generated fantasy world. It is built upon a voxel game engine that supports 3D rendering via Vulkan and Metal, utilizing a procedural world generator to create geography and ecosystems based on erosion algorithms and temperature maps. The project is distinguished by a sandboxed plugin system using WebAssembly, which allows for the addition of new game logic and equipment without recompiling the core engine. It also features a dedicated game server architecture designed to synchronize state, ma

Minetest is an open-source voxel game engine and platform used to create and share moddable 3D block-based games. It provides a framework for building interactive grid environments and generating custom voxel worlds. The project features a Lua-based modding framework that allows for the extension of game behavior and the addition of custom content without altering the core engine. This data-driven system supports a dedicated workflow for modifying game environments and logic. The engine supports multiplayer game hosting through a dedicated server architecture, enabling multiple players to co

devilutionX is an open-source, cross-platform reimplementation of the original Diablo 1 game engine. It is a software framework designed to run the original action RPG logic and mechanics on modern operating systems by rewriting the engine in a current programming language. The project modernizes the legacy experience by adding support for widescreen resolutions, high-definition scaling, and configurable input mapping for various hardware controllers. It also introduces quality-of-life enhancements such as health bars, auto-loot, and tools to modify game speed and combat rules. The engine co

Bloxstrap is a custom game bootstrapper and configuration tool for Roblox. It replaces the standard launcher to enable advanced startup configurations, inject internal engine flags, and manage a specialized installation directory. The project provides a client mod manager that allows users to override local assets, such as sounds, textures, and fonts, and ensures these customizations persist across game updates. It includes a configuration utility to unlock hidden graphics settings and engine parameters, alongside a server tracker that identifies the geographic location of active game servers

OpenTTD is an open-source game engine and transport simulation game. It provides an isometric sandbox environment for building and managing complex logistics and transport networks. The project functions as a multiplayer simulation sandbox where users can build infrastructure cooperatively or competitively in a shared virtual world. The platform is designed as a moddable simulation system that supports external assets, graphics, and gameplay modifications. It includes mechanisms for downloading and integrating add-on content and utilizes a plugin-based system to extend game mechanics beyond t

The Source Engine SDK is a C++ game development kit and modding framework designed for creating game modifications and custom gameplay extensions for the Source engine. It provides a structured environment and a collection of source code and binaries required to build custom content for compatible titles. The kit serves as a toolset for C++ game engine programming, enabling the development of custom gameplay mechanics, new rulesets, and game modes. It includes the libraries and headers necessary to compile and build gameplay extensions and custom game content.

Battle for Wesnoth is an open-source turn-based strategy game set in a high fantasy world, built around hex-grid tactical combat. At its core, it is both a complete game and a game engine, offering single-player campaigns and multiplayer battles where players command faction-specific units across terrain that provides tactical advantages. The project is fundamentally a turn-based strategy game with a dedicated multiplayer platform, supporting online and local matches with replay recording and playback. What distinguishes Wesnoth is its deep commitment to custom content creation and modding. T

Endless Sky is an open-source space trading simulation, 2D space combat simulator, and narrative exploration game. It functions as a plugin-based game engine that allows users to explore a vast universe, engage in tactical ship battles, and progress through a central plot within a sandbox environment. The project is distinguished by its highly moddable architecture, utilizing a directory-based plugin system and data-driven entity definitions to allow for content extensions and behavior overrides without recompiling source code. It further supports visual customization through programmable ver

FiveM is a multiplayer modification framework and game engine modding tool. It serves as a platform for creating and hosting community-driven modifications for open-world game engines, functioning specifically as a framework for Grand Theft Auto V to enable custom servers and multiplayer game modes. The project provides a dedicated game server host for managing network traffic and synchronized game states in modified environments. Its capabilities extend to modding Red Dead Redemption 2, allowing for the extension of game mechanics and the addition of custom content. The framework supports c

Fabric API is a modular framework designed for Minecraft mod development, providing a standardized set of hooks and libraries that enable the integration of custom content into the game. It serves as a foundational toolkit for injecting custom logic, assets, and networked data into the game environment during both startup and runtime phases. The framework distinguishes itself by facilitating interoperability between independent modifications through shared events and interface-based contracts, which allow different mods to interact without requiring direct dependencies. It manages the complex

ET is a C# game server framework and distributed actor model runtime designed for large-scale multiplayer environments. It provides a comprehensive toolkit for building distributed game backends, incorporating a multiplayer network transport layer and a specialized suite for game AI and pathfinding. The framework is distinguished by its use of a distributed actor model to scale processing across multiple threads and servers, utilizing isolated actors for state management and messaging. It features a unified codebase architecture that allows shared logic between the server and client, enabling

jvm-sandbox is a bytecode instrumentation framework and plugin container for the Java Virtual Machine. It acts as a runtime application modifier that enables the injection and modification of bytecode in a running process without requiring an application restart or changes to the original source code. The system provides a non-invasive aspect-oriented programming framework to intercept method execution and alter behavior in live processes. It functions as an isolated environment for functional modules, employing a custom class loader hierarchy to prevent dependency conflicts between plugins a

Defold is a cross-platform game engine and integrated development environment used to create 2D and 3D games for desktop, mobile, and web targets. It combines a game development IDE for asset and scene management with a multi-platform build system and a scripting environment based on Lua. The engine includes a specialized headless runtime for hosting game servers and performing automated testing without a graphical interface. It supports native engine extensions, allowing custom low-level code to be integrated into the core to expand functionality beyond the standard scripting interface. The

NeoForge is a development framework and programming interface designed for modifying the Minecraft Java Edition game engine. It provides a standardized environment that allows developers to inject custom logic, extend core gameplay mechanics, and introduce new content into the game. The platform distinguishes itself by utilizing a system of hooks and registry patterns that manage how modifications interact with the game engine. It maintains stability across different versions by separating client and server execution environments and automating the discovery and loading of mod packages. The

Impacket is a Python network protocol library and packet crafting framework used for constructing, modifying, and sending raw network packets. It functions as a network protocol manipulation toolkit that allows for the implementation of communication protocols through structured object models. The project provides a Windows network security toolkit specifically designed for interacting with Active Directory and SMB services. It enables network security testing and auditing of Windows environments by executing authentication sequences using passwords, hashes, tickets, or security keys. The li

Cubyz is a voxel game engine designed for building procedurally generated 3D sandbox worlds. It provides a framework for creating infinite landscapes with real-time terrain modification and exploration, supported by a dedicated voxel rendering engine. The project features a procedural terrain generator that utilizes a chunk-based system to allow for massive vertical construction without height or depth limitations. It optimizes performance through a distance-based rendering system that simplifies the geometric complexity of distant landscape elements to maintain wide view distances. The engi

This repository is a comprehensive collection of functional 2D and 3D demo projects and implementation samples for the Godot Game Engine. It serves as an interactive tutorial and reference library, providing a working codebase to demonstrate how to apply engine features in real-world scenarios. The collection focuses on practical implementation guides, covering a wide array of technical capabilities from basic engine fundamentals to advanced rendering and scripting techniques. It allows users to study the application of node-based composition, asset pipelines, and game logic through direct ex

Amethyst is a data-driven game engine written in Rust for building high-performance 2D and 3D games. It is built on an entity component system architecture that decouples game state from logic to enable parallel processing and reusable code. The framework features a glTF 3D renderer for importing scenes and geometry using physically based materials. It also serves as a multiplayer game framework, providing network transport abstractions and state synchronization for real-time online experiences. The engine covers a broad range of capabilities, including hybrid 2D/3D rendering, asynchronous a

This project is a World of Warcraft server emulator that simulates a multiplayer online game world, managing player data and game logic. It functions as a modular game server framework and an NPC AI and scripting engine, providing the necessary infrastructure to host a persistent virtual environment. The system is distinguished by a modular framework that allows for the extension of core engine behavior through isolated modules and function hooks without modifying the source code. It includes a structured SQL data layer for managing authentication, character states, and world environment sett

React Refresh Webpack Plugin is a development tool that enables live reloading of React components while preserving their local state during development. It integrates with build processes to instantly update component code without losing user state or session data, while also offering options to clear and reinitialize component state when unstable interfaces need clean recovery. The plugin manages updates and state preservation in the browser by intercepting the bundling lifecycle, applying abstract syntax tree transformations to inject metadata and preamble hooks, and communicating with mod

This project is an Xcode runtime code injector and developer productivity tool. It enables the injection of Swift and Objective-C code changes into a running application without requiring a process restart, functioning as a hot module replacement tool for iOS development. The tool provides a dynamic UI debugger for reloading storyboards and tuning visual parameters in real time. It allows for the recompilation of individual classes and the binding of new implementations into a live process, avoiding full project rebuilds. The system covers runtime injection capabilities, including automated

Webpack-hot-middleware is a development middleware and plugin that connects backend servers to web clients for live reloading and real-time bundle updates. It functions as an Express development middleware that streams real-time bundle updates and compiler events to web browsers, enabling automatic browser reloading and hot module replacement as source files change during development. The system incorporates compiler hook integration to listen to build lifecycle events and detect newly generated assets automatically. It establishes persistent server-sent event streams from the backend to conn

CyberEngineTweaks is a modding framework for Cyberpunk 2077 that provides a suite of tools for engine patching, scripting extensions, and the creation of interactive in-game modification interfaces. It functions as a scripting engine extension and patching tool designed to modify engine behavior and add custom game logic. The project distinguishes itself by combining a script-injection framework with a graphical user interface library, allowing for the development of custom settings menus and overlays directly within the game engine. It enables low-level engine modifications to improve perfor

Devspace is a Kubernetes development workflow tool and declarative deployment orchestrator. It automates the build, deploy, and debug cycle for applications running inside Kubernetes clusters, functioning as a container image pipeline automator and a remote Kubernetes debugger. The project features a Kubernetes hot reloading engine that provides real-time code synchronization and bi-directional file synchronization between local filesystems and running containers. This allows for updates without requiring image rebuilds or restarts. It further enables environment parity by running build, test

InjectionIII is a suite of development utilities designed for runtime code reloading, expression evaluation, and automated code injection. It provides a system for recompiling modified source files and patching function pointers in a live process to update application behavior without requiring a full restart. The project utilizes Xcode build script extensions and a live code injector to deliver Swift and Objective-C changes to desktop applications and physical hardware. It features a runtime evaluator that executes string-based Swift expressions to inspect state and retrieve values from a ru

Mindustry is a cross-platform game engine and factory automation simulation that combines resource management with tower defense strategy. Players construct complex supply chains and automated networks to process materials while building defensive structures to protect a core from waves of hostile mechanical forces. The project utilizes a deterministic lockstep networking model to ensure simulation consistency across desktop and mobile devices. It is built on an entity-component-system architecture and a tile-based grid simulation, allowing for the efficient management of thousands of active