Open Source Game Engines

Amazon Lumberyard is (or was) a free AAA-capable game engine developed by AWS, with deep integration into AWS cloud services and the Twitch streaming platform. It provided full source access and offered developers tools to build high-quality games and simulations with networking, rendering, physics and cloud backend features built in. The engine allowed game creators to hook into AWS infrastructure for multiplayer services, analytics, voice chat, and more, and leveraged Twitch to build live-stream-enabled experiences. Although Amazon has since archived the repository and transitioned focus to the open-source successor Open 3D Engine (O3DE), the project remains of interest as a large-scale example of cloud-enabled game engine architecture. Developers studying game tech or infrastructure integration can inspect how the engine’s subsystems were designed, including entity/component architectures, rendering pipelines and networked game services.

CoffeeMud is a text-based virtual reality game engine (a MUD). It is a mature, full-featured Java codebase. It includes web (HTTP) and email (SMTP) servers, chat (IMC2 and I3) and web clients, and supports ANSI, MXP, and MSP.

Ambient is an open-source, cross-platform runtime and engine for building and deploying high-performance multiplayer games and 3D applications, using a modern stack built on Rust, WebAssembly (WASM), and WebGPU. It aims to make multiplayer game development accessible and flexible, providing an entity-component-system (ECS) at its core that doubles as a real-time in-game database; everything in the game — from world objects to runtime data — is represented as entities + components, which can be synchronized across clients automatically. Ambient supports a package-based workflow reminiscent of Rust’s crate system, where “packages” bundle code, assets, and schema definitions; this modular design encourages reuse, mixing, and sharing of content. The engine includes an asset pipeline that can stream and load common 3D formats (e.g. GLB, FBX) on demand, so players don’t need to pre-download large asset bundles — the engine handles asset streaming.

Ebitengine (formerly known as Ebiten) is a lightweight, open-source 2D game engine built for the Go programming language. It is designed to be simple and easy to use, allowing developers to build games quickly with a clean and minimal API. Ebitengine supports cross-platform deployment, including desktop, mobile, web, and select console platforms. The engine provides essential features such as 2D graphics rendering, input handling, and audio playback. Developers can work with transformations, shaders, and offscreen rendering to create polished visuals. Built-in support for keyboards, mice, gamepads, and touch input ensures flexible control schemes. Overall, Ebitengine focuses on productivity and portability while maintaining strong performance.

AndEngine is a Java-based, open-source 2D game engine for Android, designed to make mobile game development easier by wrapping OpenGL (GLES) under a higher-level API. It abstracts much of the complexity of directly using OpenGL, letting developers more quickly build games with sprites, tilemaps, physics (via extensions), animations, and input handling, all within the Android ecosystem. Because it's tailored for Android, AndEngine integrates with typical Android project structure and lifecycle, although historically it was more aligned with Eclipse — meaning some adaptation might be needed for modern Android Studio projects. It enjoys a substantial community, many forks and extensions (for physics, tilemaps, multiplayer, live wallpapers, etc.), which increases its versatility — from simple casual games to more feature-rich 2D titles.

A browser game framework implemented with Grails. The goal of Little Goblin is to create a game engine that allows you to "just add content" and you will be able to host a game that is only limited by your creativity.