Tsubu (粒) means grain — and every sprite you have ever loved started as a single one. A lit window. A health pip. The first pixel of a character who would go on to carry a whole game. Tsubu is a free, browser-based pixel art studio built around that idea: start with one grain, and end with art your game engine can actually use.
If you make games, you know the gap that usually sits in the middle. You draw in one tool, wrangle frames in another, hand-pack a sprite sheet, hand-write an atlas, and pray the coordinates line up. Tsubu closes that gap. It is one place to draw, animate, generate, and export — no install, nothing to lose, and free while we're in early access.
Made for the person shipping the game
Tsubu is not a toy pixel painter. It is a keyboard-first editor with the tools you reach for a hundred times a day — pencil, eraser, fill, eyedropper, select & move — plus a real palette workflow so a whole tileset or character roster stays consistent. Grids go up to 256×256, square or not, because your UI icons and your boss sprites don't live at the same size.
Everything is saved to the cloud and reachable from any browser. Start a walk cycle on the studio desktop; fix a stray pixel from a laptop on the train. Sign in with Google and your library is just there.
From a text prompt to editable pixels
Sometimes you need a first pass, fast. Describe what you want — "a tiny knight with a red cape", "a 16×16 potion bottle" — and Tsubu's AI drafts a finished sprite in the proportions and palette discipline of real pixel art. Readable silhouettes, limited palettes, clean outlines. Not a noisy, downscaled photo.
The important part: what you get back is real pixel data on your canvas, not a flattened image. Every cell is editable. Recolor the cape, fix an outline, redraw a limb. The AI gives you a strong starting grain; you grow the sprite from there.
Animation that stays honest
Build walk cycles, idle bobs and attacks on a filmstrip timeline. Duplicate and reorder frames, preview the loop at your chosen FPS, and keep every frame as plain, editable pixels — never baked, never locked.
The part that usually hurts: export
This is where Tsubu earns its place in your pipeline. Export an animation as a single packed PNG plus a JSON atlas in the familiar Aseprite / TexturePacker shape — frame rects, durations and metadata included. It drops straight into the engines you already use:
- Unity — slice it in the Sprite Editor
- Godot — load the sheet and atlas
- Phaser and PixiJS — feed the atlas directly
Need a still? Export a clean, scaled PNG (1×–8×) with transparency preserved. Need a quick share? Animated GIF, one click.
Free while we're in early access
The whole studio — editor, animation, AI generation and export — is free for early adopters for a limited time, with usage sponsored by the platform. No credit card. No catch. Try it on your current game jam; it costs nothing but the time to draw your first grain.
Start now — it's free, or read more about generating pixel art with AI and making sprites for your game engine.
We're building Tsubu in the open, and this blog is where the workflow tips, sprite breakdowns and product updates will land. Subscribe to the RSS feed and start with a single grain.