Open-source alternatives to Fivem

tModLoader is a modding framework and toolset designed for expanding game content and extending core game logic. It provides a polymorphic content API that allows for the creation of new items, NPCs, projectiles, and world assets through object-oriented inheritance. The project is distinguished by its advanced code modification capabilities, utilizing intermediate language bytecode patching and reflection-based private access to alter internal game behavior. It features a hot-reloading assembly runtime that enables developers to recompile and apply source code changes in real-time without res

The GoldSrc game engine is a 3D game framework and first-person shooter engine designed for building and running interactive software. It functions as a moddable game framework, providing a system for creating custom game rules and content through client-side code and shared libraries. The project includes a game engine SDK and development tools for compiling custom game logic into dynamic link libraries. This modular structure allows for the development and distribution of game modifications on Windows and Linux platforms.

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

Paper is a high-performance server implementation for hosting multiplayer Minecraft games. It functions as a performance-oriented game engine designed to reduce resource usage and resolve mechanical inconsistencies in game logic. The project provides a platform for extending server logic and adding custom gameplay features through a dedicated plugin API. This allows for the development and integration of third-party extensions to add specialized capabilities to the server environment. The software covers several technical areas including server performance optimization for high-concurrency e

Turbulenz Engine is a cross-platform game engine and HTML5 framework designed for rendering graphics and simulating physics across desktop, mobile, and web environments. It functions as a WebGL graphics engine and a web-based physics engine, providing the necessary tools to build 2D and 3D games that run within browsers. The project includes a real-time multiplayer framework that synchronizes game states and player interactions between multiple users via server-side communication. This allows for the coordination of both real-time and asynchronous turn-based actions to maintain a consistent s

This repository contains the original source code for a classic real-time strategy game, serving as a legacy game engine implementation for managing units, maps, and combat mechanics in a military strategy setting. It functions as a real-time strategy game source code archive intended for preservation and technical study. The codebase acts as a game modification base, allowing developers to create custom content and modifications using the original source. It provides a foundation for retro game modding and software archeology to analyze how historical game mechanics were programmed. The pro

This project is a game server management panel and multi-user administration tool. It provides a centralized web interface and orchestrator for deploying, configuring, and monitoring game servers running inside isolated Docker containers. The system manages the full lifecycle of server instances, from mapping network allocations and IP addresses to enforcing resource limits through containerization. It includes a hosting dashboard for handling server backups via local or cloud storage and a control plane for remote-agent communication with server nodes. Administrative capabilities cover role

TrinityCore is an open-source game backend and MMORPG game server emulator. It is implemented as a C++ game engine designed to handle real-time network traffic and game state synchronization, utilizing a MySQL database schema to store player profiles, inventories, and world state. The project provides the infrastructure necessary for MMORPG server hosting and private game server administration. It includes tools for game world customization, allowing for the modification of game mechanics, item statistics, and quest scripts. The system manages virtual world infrastructure through multi-threa

Unciv is an open-source, cross-platform turn-based strategy game and a community-driven remake of a commercial strategy title. It simulates empire building, city management, and technological research for players on Android and desktop platforms. The project is designed as a moddable game engine, allowing users to override gameplay rules, modify units and buildings via external definition files, and replace audiovisual assets. It supports the distribution of custom maps and the ability to import mod archives from remote web addresses. The application includes a dedicated server for multiplay

Warzone 2100 is an open-source real-time strategy game engine focused on tactical combat and base building. It operates as a real-time strategy game engine utilizing a data-driven asset pipeline and providing cross-platform support. The project features a modular unit design system that uses a technology tree to construct combat entities by combining chassis, propulsion, and weapon components. It includes a lockstep multiplayer network engine to synchronize game state across distributed clients for competitive matches, as well as a JavaScript game scripting framework for implementing custom l

This project is an open-source 3D game engine designed for building high-fidelity games, simulations, and cinematic environments. It functions as a robotics simulation platform with native integration for ROS 2 to model robot controllers and sensors. The engine features a multi-threaded Forward+ physically based renderer that supports hardware-accelerated ray tracing and global illumination. The system is built on a modular extension architecture using Gems to add or replace features without modifying core binaries. It includes a native SDK for AWS cloud integration, enabling IAM authenticati

PartyKit is a serverless WebSocket backend platform for building real-time multiplayer applications. It provides a globally distributed edge computing runtime that runs stateful server code close to users, with automatic scaling and hibernation for idle rooms. The platform handles WebSocket connections, HTTP requests, and durable storage without requiring infrastructure management, and includes a client and server SDK with hooks, storage, and Yjs integration for building collaborative features. The platform distinguishes itself through per-room isolation using Durable Objects, where each uniq

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

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

Geode is a game modification SDK and mod loader for Geometry Dash. It functions as a hooking engine and UI framework that allows for the injection of dynamic libraries to alter game behavior and add new features. The toolkit distinguishes itself through a centralized mod compatibility manager and hook registry that tracks active modifications to prevent logic conflicts and application crashes. It utilizes a trampoline-based hooking engine to redirect game function calls while preserving native call stacks, alongside a dedicated UI framework for rendering custom popups and interface components

Pumpkin is a high-performance Minecraft game server implementation designed to host shared virtual worlds. It is specifically built to support multiple client editions, allowing different game versions to interact within a single world. The project distinguishes itself through a flexible plugin architecture that supports extensions written in Go and Python. These extensions are loaded as portable binary modules, enabling developers to implement custom game logic and modify server behavior without altering the core codebase. The server covers a broad range of operational capabilities, includi

Sol2 is a C++ Lua binding library that serves as a language interoperability layer for integrating Lua scripts into C++ applications. It acts as a scripting wrapper and API toolkit, enabling the execution of Lua code and the management of shared state within a native C++ environment. The library focuses on automated function and type mapping to bridge native C++ classes and complex data types with the Lua scripting engine. It provides mechanisms for bidirectional data exchange, allowing compiled logic and variables to be synchronized between the host application and the script runtime. The s

This project is a browser-based, real-time multiplayer action game where players control a character on a 2D canvas to absorb objects and grow in size. It utilizes a Node.js game server and WebSockets to synchronize game state, player movement, and chat across all connected participants. The application is delivered as a dockerized game application, ensuring consistent hosting and deployment across different cloud environments through containerized server environments. The system implements an authoritative server model that processes all game logic and physics to prevent cheating and mainta

This project is a Lua-based firmware environment for the ESP8266 WiFi chip, providing an embedded Lua interpreter and a development framework for WiFi SoC hardware. It functions as a C-based wrapper around the Espressif non-OS SDK, enabling the execution of asynchronous scripts to manage wireless communication and hardware peripherals. The environment integrates a SPIFFS flash filesystem for storing persistent scripts and data directly on non-volatile memory. To optimize limited hardware resources, the system utilizes execute-in-place flash execution, running read-only constants and instructi

Cuberite is a high-performance multiplayer game server for Java Edition clients, designed to provide a low-memory and low-CPU environment for hosting shared virtual spaces. The server is built for cross-platform deployment across various operating systems and hardware types. It allows for the extension of game mechanics and server logic through a Lua scripting interface, enabling functionality changes without recompiling the core engine. The project includes tools for server administration via a remote console and world data management for analyzing statistics and optimizing save file storag

Leaf is a game server framework written in Go designed for building multiplayer game backends. It provides a modular backend architecture that organizes server logic into independent modules and includes a concurrent task scheduler for managing ordered, delayed, or recurring functions. The framework features a TCP and WebSocket server that manages simultaneous connections through a single interface. It incorporates a message router capable of decoding Protobuf and JSON data to map incoming network packets to specific internal server modules. The system includes capabilities for multi-protoco

Pomelo is a distributed Node.js game server framework designed for building scalable multiplayer game backends and real-time web applications. It employs a multi-process architecture to distribute application logic horizontally across a cluster of machines, enabling high concurrency and balanced network traffic. The framework utilizes a WebSocket communication layer to manage bidirectional data exchange between diverse web clients and server clusters. It incorporates a remote procedure call system for triggering functions across remote server processes and uses Protocol Buffers for binary ser

Nakama is a distributed server framework designed for real-time multiplayer games and social applications. It provides an authoritative runtime environment for executing game logic, ensuring consistent state and cheat-resistant gameplay across diverse client platforms. The system acts as a centralized backend, managing persistent player identities, social graphs, and real-time communication channels to support complex multiplayer interactions. The platform distinguishes itself through an integrated suite of LiveOps tools that allow developers to manage game economies, schedule time-bound even

OpenRCT2 is an open-source reimplementation of a classic amusement park management simulation engine. It functions as a cross-platform engine that modernizes the original game, enabling it to run on contemporary operating systems while maintaining full compatibility with legacy assets and data files. The project distinguishes itself by providing a comprehensive multiplayer simulation server that supports cooperative, real-time park management and construction across multiple connected clients. It utilizes a deterministic lockstep networking model and a centralized action-based validation syst

GDevelop is a no-code game engine designed for building interactive 2D applications through a visual scripting environment. It allows users to define game logic and object interactions using a graphical interface of conditions and actions, eliminating the need for traditional programming. The platform functions as a cross-platform creator, enabling the export of projects to web, desktop, and mobile environments from a single codebase. The engine is built on a modular game development extension framework that supports the creation and sharing of reusable behaviors and logic components. Develop

This project is a networked first-person shooter framework built for the Unity game engine. It provides a foundational architecture for managing multiplayer sessions, enabling real-time synchronization of player movement, health, and combat actions across all connected clients. The framework utilizes an authoritative server model to maintain a consistent game state, supported by remote procedure calls to handle networked events. It incorporates a component-based entity system to define gameplay logic and uses state machines to manage character animations, ensuring smooth transitions between m

LuaViewSDK is a cross-platform UI engine and framework that uses a Lua-based scripting engine to render native user interfaces across multiple mobile operating systems. It functions as a dynamic UI orchestrator, separating interface logic from the underlying operating system to allow for the creation of native views driven by scripts. The system features a bidirectional native scripting bridge for exchanging data and triggering functions between the script runtime and native platform APIs. It also includes a Lua game runtime capable of executing interactive graphics and lightweight games thro