Third-party licenses
Aback Chess is built with open-source components. Their licenses and attributions are listed below.
chess.js
BSD-3-ClauseChess rule validation, FEN and PGN parsing, and SAN generation.
https://github.com/jhlywa/chess.jsPlus Jakarta Sans
SIL Open Font License 1.1The typeface used across the interface.
https://github.com/tokotype/PlusJakartaSansGeist Mono
SIL Open Font License 1.1The monospace typeface for FEN, PGN and engine lines.
https://vercel.com/fontChess piece artwork (Cburnett set)
GFDL / BSD-3-Clause / GPL-2.0+Standard chess piece SVGs by Colin M.L. Burnett, distributed via Wikimedia Commons. Used for board piece rendering.
https://commons.wikimedia.org/wiki/Category:SVG_chess_pieces@tabler/icons-react
MITInterface icons.
https://tabler.io/iconsNext.js
MITApplication framework.
https://nextjs.orgTailwind CSS
MITStyling utilities.
https://tailwindcss.comLichess puzzle database
CC0-1.0The puzzles, their ratings and themes come from the open Lichess puzzle database, released into the public domain under CC0.
https://database.lichess.org/#puzzlesStockfish 18 (via stockfish.js)
GPL-3.0Stockfish 18 with its NNUE evaluation, compiled to WebAssembly by Nathan Rugg (nmrugg/stockfish.js, sponsored by Chess.com) and distributed as part of Aback Chess under the GNU General Public License v3. The engine runs entirely in the browser. The full license text is included at public/engine/Copying.txt. Stockfish is a separate project by T. Romstad, M. Costalba, J. Kiiski, G. Linscott and contributors.
https://github.com/nmrugg/stockfish.js