LunarEngine (formerly Librebox) is an open-source game engine powered by Luau. It delivers a sandbox-style API and development model inspired by popular sandbox engines, so existing Luau code runs with minimal changes.
Open Source Unity Alternatives
The best open source alternative to Unity is Godot Engine. If that doesn't suit you, our users have ranked more than 100 alternatives to Unity and loads of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Unity are GDevelop, Candlestick, Stride Game Engine and GABE.
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Most Unity alternatives are Game Development Tools, but you can also narrow the list to Role-playing Games or IDEs. Other popular filters are 3D Game Engine, Linux, Open Source, Online and Free. You can also filter for EU-based alternatives if you prefer software from the European Union.
Alternatives list
Cost / License
- Free
- Open Source (MIT)
Since
- Since 2025
Whitestorm.js is a framework for 3D web apps built with Three.js technology. It implements a core for fast development of a 3D scene with physics.
Russia
+1
ZGameEditor lets you create 3D games with procedural content that have a redistributable size of 64 KiB or less. It consists of a lightweight OpenGL-powered engine that runs on Windows, Mac, Linux & Android, and a portable Windows IDE featuring real-time editing.
Sweden
EU
+1
A game engine written in Python, extending support across multiple GPU devices with 3D rendering, PBR Renderer and much more.
Cost / License
- Free
- Open Source (Apache-2.0)
Since
- Since 2024
Orx is an open source, portable, lightweight, plugin-based, data-driven and extremely easy to use 2D-oriented game engine. Orx is mostly written in C, but allows you to develop with it with any language that can interface to C.
+3
QICI Engine is a free and opensource JavaScript library, based on free and opensource game engine Phaser, with a web-based comprehensive suite of HTML5 game making editor.
United Kingdom
A cross-platform 2D game prototyping framework based on OpenGL and C++.
Angel balances the speed and flexibility of native code with an eye towards rapid iteration and out-of-the-box functionality. In a world of web games and memory-managed scripting engines, sometimes you still.
LittleJS is a fast lightweight open source HTML5 game engine for modern web development. Its small footprint is packed with a comprehensive feature set including hybrid rendering, physics, particles, sound effects, music, and input handling.
69 FPS Creator alternativesFPS Creator is a complete drag-and-drop game-making tool that lets you build your own first-person shooter games without writing a line of code.
- United Kingdom
United States
