Runtimes

One rig.
Every engine. Every frame.

Export once and play the same animation in Godot, Unity, Defold, Cocos Creator, Phaser, the browser or Rust. Seven official runtimes, free for any game, tested against each other frame by frame on every commit.

Pick your engine Runtime guide

Live, in your browser

How many NILAs can your device run?

Each NILA has 39 bones, 890 mesh vertices and physics on her braid. This is the JavaScript runtime and its WebGL renderer, the same code a web game ships, and the slowest of the seven. The native runtimes are 3 to 4 times faster.

Characters: 10
Animation, per frame: –
Per character: –
Drawing: –

Official runtimes

Every one is maintained here, ships with each release and passes the same tests. No community ports to hope for.

Godot RigbySkeleton2D and RigbyScene2D nodes, a GDExtension on the Rust core. Godot 4.3+ · Windows, macOS, Linux Unity Components in C#, posing on every core, no garbage in steady playback. Unity 2021.3+ and Unity 6 · every platform Defold New A native extension in C++ with a Lua player. One dependency URL. Defold 1.14+ · every platform Cocos Creator A RigbySkeleton component that draws in order with sprites and UI. Cocos Creator 3.8 · web and native Phaser A plugin: this.load.rigby() and this.add.rigby(). One file. Phaser 3.60+ and Phaser 4 · WebGL JavaScript The reference runtime and a WebGL renderer, no dependencies. Any browser or JS engine Rust The rigby-runtime crate, no dependencies, 3 to 4 times faster than JavaScript. Any target Rust builds for

In the editor, File ▸ Get runtimes downloads the ones that match your version, or installs them straight into a Godot or Cocos project.

Why Rigby2D runtimes

Already using Spine? Your exports play in Rigby2D runtimes as they are. Here is what changes.

	Rigby2D runtimes	Spine runtimes
Cost	Free. MIT or Apache-2.0, for any game, any studio, any revenue.	Need a Spine editor license.
Defold, Cocos Creator, Rust	Official, released and tested with the editor.	Listed as third-party runtimes, maintained by the community.
Scenes	Whole scenes play in the engine: several characters on a stage, clips with crossfades, a camera with parallax.	One skeleton at a time; the scene is built in each engine.
File versions	One runtime reads them all: skeleton JSON 3.8, 4.2 and 4.3 and binary .skel 4.3.	Each runtime version reads exports of its own editor version.
Getting them	From the editor: File ▸ Get runtimes, matched to your version.	From the runtimes repository, by hand.

Spine is a trademark of Esoteric Software. Rigby2D isn't affiliated with it; this compares the published runtime licenses and lists as of November 2026. See also Rigby2D vs Spine.

Correct

Frame for frame, to eight decimal places

The JavaScript runtime is the reference. Golden files record what it does with every demo rig: bone matrices, vertices, colors, draw order and events, for every animation, crossfades, layered tracks, queues and skins. The Rust, C++ and C# runtimes replay them on every commit and must match.

See the CI workflow

Largest relative difference from the JavaScript runtime
Rig	Bone matrices	Vertices
Rigbytron	2 × 10⁻¹⁶	1 × 10⁻¹⁵
NILA, with physics	3 × 10⁻¹¹	3 × 10⁻⁹
Scene: NILA and Rigbytron on a stage	2 × 10⁻¹²	5 × 10⁻¹¹
16 sample rigs, 3,500 frames	under 10⁻¹⁰ relative

Fast

Native speed where it counts

Posing a character means animation, IK, transform, path and physics constraints, world transforms and every mesh vertex. The native cores do it in microseconds and allocate nothing in steady playback.

Unity: 200 NILAs in 5.0 ms a frame on a 4-core laptop, upload included.
Defold: NILA posed in 12 µs, her geometry built in 24 µs, written straight into vertex buffers.
Rust: 3 to 4 times faster than JavaScript on every rig.

One character, one frame (median of 2,000)
Rig	JavaScript	Rust
67 bones, 276 mesh vertices	50 µs	14.5 µs
76 bones, 667 weighted vertices, 9 IK	71 µs	22 µs
143 bones, 879 vertices, 21 constraints	90 µs	22 µs

Everything the editor does, in your game

Meshes and weightsDeform keysLinked meshesIK, one and two bones Transform constraintsPath constraintsPhysicsSlidersSkins Image sequencesClippingDraw order keysTwo-color tintBlend modes Events with audioLayered tracksCrossfadesQueued animations Bone followersScenes with cameras

Formats: skeleton JSON 3.8, 4.2, 4.3 · binary .skel 4.3 · texture atlas · .scene.json.

Ship it anywhere. Pay nothing.

The editor and every runtime are free and open source, for commercial games too.

Download Rigby2D Open the browser editor Source on GitHub

One rig.Every engine. Every frame.