SpineBones
SpineBones is a free 2D skeletal animation editor for creating bone rigs, animating them with timeline keyframes, and exporting finished work.
What SpineBones is
SpineBones is a free 2D skeletal animation editor for creating bone rigs, animating them with timeline keyframes, and exporting finished work. Rigging tools include bone hierarchies, re-parenting, grouping, and inverse kinematics. Its timeline supports keyframe editing and looping, per-key easing, and audio tracks. Artwork slots accept PNG, JPG, SVG, and WebP files, with multiple attachments per slot and frame-by-frame swaps. You can deform attachment meshes with keyed vertices and use onion skin to view nearby poses. SETUP mode holds the base pose; ANIMATE mode is for keying position, rotation, and scale. Exports include WebM video, transparent PNG sequences, sprite sheets with atlas data, and portable .sbn project packages; the editor can also open legacy .json projects. An MCP bridge works with Claude and other MCP clients to create rig elements and keyframes, adjust frame rates, and start exports. SpineBones runs on macOS 12 or newer and Windows 10 or newer, and is free to download without an account, licence key, or trial timer.
Good
- Free plan with no account or licence key
- Supports inverse kinematics and bone hierarchies
- Exports WebM, PNG sequences, and sprite sheets
- Includes mesh deformation and onion skin
- MCP bridge can create rigs and trigger exports
Watch out
- Limited to macOS and Windows
- Free plan has a 300-frame timeline
- Playback is capped at 120 FPS
Who it suits
SpineBones suits 2D animators who need skeletal rigging and timeline tools, including workflows that export sprite sheets for game engines or PNG sequences for compositing. It also fits users who want portable project packages or MCP-client integration.
Verdict
SpineBones brings rigging, keyframe animation, and multiple export formats into a free editor for macOS and Windows. Its 300-frame timeline and 120 FPS playback limit are worth noting.
Plans and prices
From SpineBones's own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | 300-frame timeline · playback up to 120 FPS · WebM, PNG sequence, and sprite-sheet exports |
The facts
Each one read from SpineBones's own pages, with the date it was checked.
Money
- Access and trial
- The app is free to download with no account, licence key, or trial timer.checked 2 Oct 2026
What it does
- Agent integration
- Its MCP bridge works with Claude and other MCP clients to create rig elements and keyframes, rescale animation frame rates, and trigger exports.checked 2 Oct 2026
- Animation modes
- SETUP holds the base pose and ANIMATE holds keyframes; the editor supports keying position, rotation, and scale.checked 2 Oct 2026
- Artwork
- Slots can bind PNG, JPG, SVG, or WebP artwork, with multiple attachments per slot and frame-by-frame swapping.checked 2 Oct 2026
- Artwork attachments
- Slots can use PNG, JPG, SVG, or WebP artwork, with multiple attachments and frame-by-frame swaps.checked 15 Oct 2026
- Bone rigging
- The editor supports canvas bone-chain creation, re-parenting, grouping, and inverse-kinematics chains.checked 15 Oct 2026
- Download formats
- The itch.io download page lists a 3.2 MB Apple-silicon DMG and a 12 MB Windows executable.checked 15 Oct 2026
- Exports
- Exports include WebM video, transparent PNG frame sequences, and sprite sheets with atlas data.checked 15 Oct 2026
- Independent description
- The itch.io listing describes SpineBones as a lightweight desktop tool aimed at practical skeletal-animation work without unnecessary complexity.checked 15 Oct 2026
- Independent export confirmation
- The itch.io listing states that projects can be exported as JSON, sprite sheets, or WebM video.checked 15 Oct 2026
- Independent feature list
- The itch.io listing confirms bone hierarchies, parent-child rigs, slots, skins, setup and animate modes, keyframes, IK, groups, audio preview, and background references.checked 15 Oct 2026
- Independent listing status
- The itch.io catalog marks SpineBones as released, authored by gevanni, and available for Windows and macOS.checked 15 Oct 2026
- Installation documentation
- The itch.io page gives Windows installer steps and macOS DMG drag-to-Applications steps, including first-run security prompts.checked 15 Oct 2026
- Intended use
- The maker describes sprite-sheet exports as sized for game engines and 2D frameworks, and PNG sequences as suitable for compositing tools.checked 2 Oct 2026
- Keyboard controls
- Dedicated shortcuts cover posing, bones, transforms, setup and animate modes, playback, keyframes, saving, opening, and undo.checked 15 Oct 2026
- Licence and account
- The official site says the app has no per-seat licence, account requirement, licence key, or trial timer.checked 15 Oct 2026
- Limit: MCP packaging complaint
- A user reported that an older Windows build lacked the MCP server bundle required for the MCP server to start.checked 15 Oct 2026
- Local operation
- The itch.io notes say normal use needs no extra libraries and that exported files and projects are written locally.checked 15 Oct 2026
- MCP actions
- MCP commands can create rig elements and keyframes, change animation frame rate, and start exports.checked 15 Oct 2026
- MCP editing depth
- The itch.io documentation says MCP can add, rename, delete, reorder, re-parent, mirror, and transform bones and can batch keyframe operations.checked 15 Oct 2026
The company
- Company fact
- An Agara Teknologi proposal names I Gst. Ngr. Ag. Pt. Kresna Putra as CEO/software developer and Ketut Pradipta Westika as CTO/software developer.checked 15 Oct 2026
- Founded
- 2020checked 28 Sep 2026
- Headquarters
- Jembrana, Bali, Indonesiachecked 28 Sep 2026
Where it runs
- Limit: platform coverage
- The published downloads and platform metadata cover only Windows and macOS.checked 15 Oct 2026
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