What is the difference between Phaser.js and Three.js?

Phaser and Three.js don't compete for the same job: Phaser is a 2D game framework with physics and scene management built in, while Three.js is a 3D rendering library that ships with none of that. Three.js has roughly 113,000 GitHub stars against Phaser's roughly 40,000, but the gap reflects what each project set out to do, not which one wins at making games.

Where does the "which one is better" question come from?

Both show up on the same "best JavaScript game library" roundups, both render to a canvas element, and both have been around long enough to build huge tutorial catalogs, so people default to lumping them together. Phaser is built specifically for 2D games. Three.js is a general-purpose 3D graphics library that shows up in product configurators, data visualizations, and WebXR demos just as often as it does in games.

Comparing them as alternatives is closer to comparing a game engine to a rendering API. One is a finished toolkit for a specific genre of app, the other is a graphics layer you build on top of.

What does each one actually include?

Phaser ships with a scene manager, an input system, tilemap support, and two physics engines out of the box: Arcade Physics for simple box collisions and a Matter.js integration for anything that needs rotation and constraints. It renders through Canvas or WebGL depending on browser support. The project went through a full renderer rewrite with Phaser 4, released in April 2026, and the changelog currently sits at v4.2.1.

Three.js only handles rendering: cameras, meshes, materials, lighting, and now both WebGL and WebGPU backends. There's no physics engine, no built-in input handling, and no concept of a game scene beyond a plain 3D scene graph, so projects add a library like cannon-es or Rapier for physics and write their own input and game-loop code. Three.js is versioned by revision number rather than semver, and the current release is r184.

How should this change what you pick?

For a platformer, puzzle game, or anything that lives on a 2D plane, Phaser gets a working prototype done faster because the physics and input plumbing already exists. For a 3D scene, product viewer, or WebXR build, Three.js is the right layer, but budget time for wiring up physics and controls yourself.

The two also aren't mutually exclusive. Developers have combined them by creating a Three.js WebGL renderer that draws to the same canvas Phaser owns, rendering the 2D layer first, resetting the WebGL state, then drawing the 3D scene on top before resetting again. The enable3d library packages this pattern so a Phaser game can host real 3D models and physics without giving up Phaser's 2D tooling.

The useful question was never Phaser versus Three.js. It's whether the project needs a 2D game engine, a 3D rendering layer, or both wired together.