Hi HN! I built a free pixel art editor that runs entirely in the browser — no install, no signup, no watermark. The frontend is open source (MIT): https://github.com/comficker/simplepixelart

What it does:

- Sprite editor with layers, selections, mirror drawing, and an infinite-canvas workspace (multiple boards on one desk)

- Frame-by-frame animation with onion skin, per-frame duration, GIF and spritesheet export

- Tileset builder that auto-generates Wang-16 and blob-47 terrain sets from a single base tile — exports Godot 4 TileSet, Tiled .tsx, or PNG+JSON — plus a tilemap painter to test terrains in the browser

- Isometric (2:1 dimetric) grid mode with an iso-line tool

- Image-to-pixel-art converter: median-cut quantization, live adjustments, and a "pixel cleaner" that removes orphan pixels

Some technical bits:

- The renderer is a hand-rolled 2D canvas — no engine, no WebGL. Pixel maps are plain objects keyed "x_y" with an incremental dirty-pixel buffer, so a brush stroke costs ~0.006ms/frame instead of rebuilding the whole map

- Guest-first storage: everything autosaves to localStorage, with the multi-board snapshot in IndexedDB to escape the ~5MB quota. An account is only needed for cloud sync and publishing to the gallery

- Favorite recent bug: fitting a workspace of 16 isometric boards took 12.4 seconds. The iso lattice was drawn as O(cols×rows) individual diamonds — every shared edge stroked twice. Rewriting it as two families of parallel lines (O(rows+cols)) brought it down to 16ms

- No CSS framework at runtime; the design system is one hand-written CSS file

Honest caveat: the repo is the frontend only. The community gallery and auth run against a hosted API, but the editor itself — drawing, animation, tilesets, conversion, exports — is fully client-side and works without an account.

Would love feedback, especially from anyone making game assets: what's missing before this could replace your current tool for quick sprites?

Show HN: Open-source pixel art editor with animation and auto-tiling tilesets