Best Open-Source Game Engines for 2026
Open-source game engines give you something proprietary ones can't: a license that won't change after you've shipped. No per-seat fees, no revenue thresholds, no surprise pricing. You can read the source, fork it, and keep building even if the original team walks away. After the Unity Runtime Fee episode, that stability is exactly why a lot of teams moved to open source in the first place.
This is the complete list of open-source game engines worth using in 2026, grouped by what they're for. The short version: Godot for an all-round 2D and 3D engine, Phaser for 2D web, Three.js or Babylon.js for web 3D, Bevy if you write Rust, and Defold if the build has to be tiny. Every version and license below was checked as of September 2026. If you specifically need a web build, we've flagged which ones export to the browser, and you can go deeper in our best web game engines comparison.
Quick comparison
| Engine | License | Language | 2D / 3D | Web export | Best for |
|---|---|---|---|---|---|
| Godot | MIT | GDScript, C# | Both | Yes (GDScript) | The all-round free engine |
| Phaser | MIT | JavaScript | 2D | Yes | 2D web games |
| PixiJS | MIT | JavaScript | 2D | Yes | Custom 2D rendering |
| Three.js | MIT | JS / TS | 3D | Yes | Web 3D, max control |
| Babylon.js | Apache 2.0 | JS / TS | 3D | Yes | Full-featured web 3D |
| Defold | Free, source-available | Lua | 2D / light 3D | Yes | Smallest web builds |
| Excalibur.js | BSD | TypeScript | 2D | Yes | TypeScript 2D games |
| Bevy | MIT / Apache 2.0 | Rust | Both | Yes (Wasm) | Rust, data-driven design |
| LÖVE | zlib | Lua | 2D | Limited | Quick 2D prototypes |
| Cocos Creator / COCOS 4 | MIT (fully open since Jan 2026) | TypeScript | Both | Yes | Mini-games, Asian market |
| O3DE | Apache 2.0 | C++, Lua | 3D | No | Large-scale 3D, AAA scope |
There's no single "best" open-source engine. The right one depends on 2D vs 3D, your language, and whether you're targeting the web.
What changed in 2026
A few things moved this year that are worth knowing before you pick. COCOS went fully open: on January 4, 2026 the company announced COCOS 4 under the plain MIT license, dropping the commercial clauses from the Cocos Creator era, and the cocos4 repository is tagged v4.0.0 with the editor split out into CLI tools. Fenris Creations (formerly CCP Games) published the components of Carbon, the engine behind EVE Online, on GitHub under MIT and other permissive licenses in 2026, as a set of libraries (core, resources, IO, math, pathfinding, and more) rather than a turnkey game engine, see the carbonengine organization. Just before the year started, Facepunch open-sourced the C# layer of s&box under MIT in November 2025, though it still sits on Valve's closed Source 2, so it's not a fully open stack. On the release side: Godot shipped 4.7 in June (4.7.2 in August, 4.8 in dev snapshots), Bevy shipped 0.19 in June, Phaser 4 landed in April, Babylon.js 9 in March, O3DE cut its 26.05 release in May, Defold 1.13.1 added light components in August, and the MIT-licensed C# engine Stride is working through 4.4 betas. Nothing changed for the worse: no engine on this list moved to a more restrictive license in 2026.
Full 2D and 3D engines
Godot
Godot is the engine most people mean when they say "open-source game engine." It's MIT licensed, does both 2D and 3D, and has no fees or revenue caps of any kind. It ships small web builds (around 5 MB Brotli or 9 MB gzipped) and, since 4.3, can export single-threaded for clean iOS and Safari support. The current stable is 4.7.2 (August 2026) with 4.8 in development. The one web caveat is that C# projects can't export to the browser yet, only GDScript, and that's still true as of September 2026 per the web export docs. For most teams leaving a proprietary engine, Godot is the closest all-round replacement. See Godot vs Unity for web games for the head to head.
Cocos Creator
Cocos Creator pairs a free editor with an open-source (MIT) runtime. It handles 2D and 3D, supports WebGL, WebGPU, and Wasm, and is especially strong for mini-game platforms like WeChat and TikTok where build size is critical. Builds land around 2 to 4 MB. Cocos Creator 3.8.8 (December 2025) is the last of the 3.x line, and since January 2026 the successor, COCOS 4, is fully MIT licensed with the engine and editor separated, so the old commercial clauses are gone. If you're weighing it against a web-first option, see Cocos alternatives.
3D libraries and engines for the web
Three.js
Three.js is the most widely used 3D library on the web, MIT licensed, with a core around 150 KB. The current release is r185 (July 2026), and its WebGPU renderer falls back to WebGL2 automatically. It's a rendering library rather than a full engine, so you add your own game systems or a framework on top. That's the trade-off: maximum control and the smallest footprint, in exchange for writing more yourself. It's the foundation we built Cinevva Engine on, layering the game systems back so you don't start from an empty canvas.
Babylon.js
Babylon.js is a full open-source 3D engine (Apache 2.0) with built-in physics, animation, a scene inspector, and strong WebGPU and WGSL support. Babylon.js 9 shipped in March 2026 and is at 9.25 as of September 2026, per the releases page. Compared to Three.js it gives you more out of the box at a larger size. See Three.js vs Babylon.js for which fits your project.
2D frameworks
Phaser
Phaser is the most popular open-source HTML5 game framework, MIT licensed, with the biggest 2D web community and ecosystem. Builds are around 500 KB. If your game is 2D and you write JavaScript, it's hard to beat.
PixiJS
PixiJS is a fast 2D WebGL renderer (MIT), around 200 KB. Like Three.js for 3D, it's a renderer rather than a full engine, so you bring your own game logic. Pick it when you want custom 2D rendering and a tiny footprint.
Excalibur.js
Excalibur.js is a friendly, BSD-licensed 2D engine written in TypeScript, around 300 KB, with more built-in game features than a bare renderer. A good fit if you want types and a gentle on-ramp.
LÖVE (Love2D)
LÖVE is a long-running, zlib-licensed 2D framework scripted in Lua. It's beloved for fast prototyping and game jams on desktop. Web export exists through love.js but is limited, so treat LÖVE as a desktop-first tool.
Rust, C++, and large-scale engines
Bevy
Bevy is a modern, data-driven engine written in Rust, dual-licensed MIT and Apache 2.0. Its entity-component-system architecture is a big draw, and it compiles to WebAssembly for browser builds. It's younger than the others and moves fast, so expect breaking changes between versions, but it has strong momentum in 2026: Bevy 0.19 shipped in June 2026 with a 0.19.1 patch in August.
Open 3D Engine (O3DE)
O3DE is a Linux Foundation project (Apache 2.0) aimed at large-scale, high-fidelity 3D, backed by AWS and others. It's a serious, heavyweight engine for teams with AAA ambitions and the resources to match. The 26.05 release (May 2026) is current. It doesn't target the browser.
How to choose
- Want one free engine for almost anything? Godot.
- Building a 2D web game? Phaser, or PixiJS/Excalibur.js for custom rendering.
- Building web 3D? Three.js for control and size, Babylon.js for batteries included.
- Smallest possible web build? Defold.
- Targeting mini-game platforms? Cocos Creator.
- Love Rust and ECS? Bevy.
- Large-scale, high-fidelity 3D? O3DE.
If the web is your target, every engine above except O3DE and (mostly) LÖVE can ship a browser build. For the full breakdown on web specifically, see the web game engines comparison and our guide to Unity alternatives for web games.
Common Questions
What is the best open-source game engine in 2026?
For most people it's Godot: MIT licensed, free with no revenue caps, and capable in both 2D and 3D with a clean web export. For 2D web specifically, Phaser is the most popular open-source pick, and for web 3D it's Three.js (a library) or Babylon.js (a full engine). The best choice depends on dimensions, language, and platform.
Is Godot really free, with no catch?
Yes. Godot is released under the MIT license, which means no fees, no royalties, no revenue thresholds, and no seats, ever. You can use it for commercial games and even modify the engine itself. The project is funded by donations and sponsorships, not by charging developers.
Are open-source game engines good enough for commercial games?
Yes. Plenty of commercially successful games ship on open-source engines, and open source means there's no revenue cap to worry about. The trade-offs are usually a smaller built-in asset marketplace and, for some engines, fewer turnkey features than a large proprietary engine. For web games in particular, open-source engines often produce smaller, faster builds.
Is Unity or Unreal open source?
No. Unity is closed-source and subscription-based. Unreal Engine is source-available (you can read and modify the code with an account) but it's not open source and uses a royalty model above a revenue threshold. If you specifically want an open-source engine, Godot is the closest equivalent to Unity, and our Unity alternatives guide covers the rest.
Which open-source game engines are new or newly open-sourced in 2026?
The big license news of 2026 is COCOS 4, fully MIT licensed since January 2026 with the commercial clauses removed. Fenris Creations also published EVE Online's Carbon engine components under MIT on GitHub, and Facepunch's s&box C# layer went MIT in late 2025 (its Source 2 base stays closed). No established engine changed to a more restrictive license this year. See the "What changed in 2026" section above for versions.
What is the best open-source 3D game engine?
Godot for a full 3D engine with an editor, and it's the one most teams pick. For 3D in the browser specifically, Babylon.js is the most complete open-source engine and Three.js is the most-used library, both with WebGPU renderers and WebGL2 fallback. Bevy is the pick if you want Rust and an ECS, and O3DE if you need AAA-scale tooling and don't need a web build. If you want to see what open-source web 3D can do before you commit, Cinevva Engine is built on Three.js.
Which open-source engine can target WebGL so players can play in the browser?
Almost all of them. Godot exports to WebGL 2.0 (use GDScript and single-threaded export), Phaser, PixiJS, Excalibur.js, Three.js, and Babylon.js are web-native, Defold ships Wasm plus WebGL builds around 1.14 MB, Bevy compiles to WebAssembly, and Cocos Creator exports to WebGL and WebGPU. The exceptions are O3DE (no browser target) and LÖVE (third-party love.js only). Run our WebGL and WebGPU checker to see what your players' browsers support.
Is there a full list of open-source game engines for 2026?
The quick comparison table at the top of this page is our list: Godot, Phaser, PixiJS, Three.js, Babylon.js, Defold, Excalibur.js, Bevy, LÖVE, COCOS 4, and O3DE, plus Stride, Carbon, and s&box in the "What changed in 2026" section. Each entry links to its license and current version so you can verify before you commit.
Which open-source game engine is best for the web?
Godot for an all-round 2D/3D engine, Phaser for 2D, and Three.js or Babylon.js for 3D. Defold ships the smallest web builds of any full engine. All of them are free and open source. Our web game engines comparison ranks them on build size, load time, and browser support.
Try the idea first, adopt the engine when you outgrow it.
Related
- Best Web Game Engines for 2026 (Compared): ranked on build size, load time, and cost
- Unity Alternatives for Web Games: open-source options for teams leaving Unity
- Godot vs Unity for Web Games: the closest open-source replacement, head to head
- Best 2D Game Engines for 2026: if your game is 2D
- Three.js vs Babylon.js: the two big open-source web 3D libraries
- Cinevva Engine: our open-source, web-first engine built on Three.js