Keyframe.it — free browser-based 2D skeletal animation for game sprites

Keyframe.it is a free, browser-based 2D skeletal animation editor. You rig your artwork with bones, deform it with weighted meshes, animate it on a keyframe timeline, and export straight to pixi-spine — all in the browser, with no install and no signup. It's especially suited to animating slot-machine and game symbols (including stake-engine games).

What you can do

• Rig characters and symbols with bones (forward kinematics) and inverse kinematics (IK).
• Mesh-deform art with bone weighting/skinning for natural bending and squash & stretch.
• Animate on a keyframe timeline and curve graph editor, with spring physics for secondary motion (tails, hair, cloth).
• AI-assisted rigging from an image, AI-assisted animation from a text description, and a scripting API any AI agent can drive.
• One-click slot-symbol animation pack — generate idle, win, drop and destroy clips at once.
• Import & export Spine bundles (.json or binary .skel + .atlas + .png) for pixi-spine and other Spine runtimes; also export GIF, sprite sheet and video; import PSD layers as parts.

Who it's for

Game developers, slot/casino-game artists, and 2D animators who want a fast, free, browser-based alternative to Spine for rigging and animating sprites and exporting to game engines via pixi-spine. Try a live demo: noir character (production rig) · rigged monkey character · cat character · slot symbol.

Frequently asked questions

Is Keyframe.it free? Yes — Keyframe.it is free to use in your browser, with no install and no signup. Optional AI-assisted rigging and animation use your own Anthropic API key.

Is Keyframe.it a free alternative to Spine? For browser-based workflows, yes. It covers bone rigging, weighted mesh deformation, IK, constraints, a dope sheet and curve editor, and exports Spine-compatible bundles that load in pixi-spine and other Spine runtimes.

Does it export to Spine / pixi-spine? Yes — it exports Spine 3.8 and 4.2 bundles (.json or binary .skel + .atlas + .png) that load directly in pixi-spine, and it can import existing Spine exports.

Do I need to install anything? No — Keyframe.it runs entirely in a modern web browser, and your work autosaves locally in the browser.

Learn more: free Spine alternative · author animations for pixi-spine · slot symbol animation.