Software with Onion Skinning

Aseprite is a pixel art editor built around sprite work: an indexed-color workflow, onion skinning and a timeline for animation, tilemap layers, custom brushes, and export straight to sprite sheets. Extensions and Lua scripts add anything it lacks. It is the editor most Lospec artists reach for first.

GraphicsGale has been in use since 2005 and excels at animation, with onion skinning and frame-by-frame preview. It was made freeware in 2017. The interface shows its age but the tools are precise.

LibreSprite continues the last GPL version of Aseprite as a community project. It keeps the familiar layers, animation timeline and palette tools, and adds its own scripting and a browser build.

Novaboard runs in the browser and as a desktop app, with layers, animation and effects.

Pixaki is a full pixel art studio for the iPad, built for drawing with the Apple Pencil rather than a mouse. It has layers, a proper animation timeline with onion skinning, palette tools and tiled preview, and exports sprite sheets, GIFs and layered files.

Pixel Studio is a pixel art editor that runs on desktop, phone and tablet with the same project open on all of them. It covers layers, animation with onion skinning, tilesets and palettes, and reads and writes Aseprite files, which makes it a practical way to keep drawing away from a desk.

Pixelorama is a full featured free editor: layers, animation with onion skinning, tile mode, palettes, and an active development pace. It runs on every desktop platform and in the browser.

Pixen is a pixel art and animation editor built as a proper Mac application, with the same project openable on an iPhone or iPad. It is aimed at low-resolution bitmaps and 8-bit sprites: layers, palettes, an animation timeline and the system features a native app gets, like versions and autosave.

Pixly is a game-oriented pixel art and animation editor for Android, with the gestures worked out for a touchscreen: two fingers to pan and zoom, three to change the brush size. It covers layers, onion-skinned animation, symmetry, real-time tiling and cloud sync. Its own site is still up and still points at Google Play as the only way to get it, but that listing no longer resolves.

Pixquare is a pixel art editor for iPad and iPhone with a deliberately dense feature set: layers, animation, palettes, tiled preview and pressure-aware Apple Pencil drawing. It reads and writes the formats desktop editors use, so a drawing started on a tablet finishes anywhere.

Resprite is a pixel art and animation editor for iOS, Android, Windows and macOS, built around a touch interface without losing the tools a desktop editor has: pixel-perfect lines, alpha lock, dithering patterns, custom brushes, gradients and symmetry. It imports and exports GIF, sprite sheets, PSD and APNG.