Last updated: September 23, 2026
Sudoku uses third-party fonts and software. Required notices are below.
The following fonts are licensed under the SIL Open Font License 1.1 and may be bundled with this software:
Playwrite IS, Klee One, Kalam, Satisfy, Caveat, Shantell Sans, Geist Pixel, IBM Plex Sans KR, Noto Sans Arabic, Lato, Montserrat, Raleway, Oswald, Source Sans 3, PT Sans, Poppins, Nunito, Dosis, Fira Sans, Bitter, Courier Prime, Source Code Pro, Doto, Playfair Display, Merriweather, Crimson Text, PT Serif, Dancing Script, Lobster, Pacifico, and Ojuju.
The OFL is available at openfontlicense.org.
Roboto is licensed under the Apache License 2.0.
Hand-drawn digit recognition is based on a TypeScript port of the $1 Unistroke Recognizer. Reference implementation: nok/onedollar-unistroke-coffee. MIT License.
Copyright (c) 2013-2016 Darius Morawiec Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Halftone, dither, and magazine color effects use Paper Shaders, licensed under the Apache License 2.0.
Paper Shaders Copyright 2026 Paper Powered by Paper Shaders: https://shaders.paper.design
Apache License 2.0: apache.org/licenses/LICENSE-2.0.
Home Zine* cover treatment adapted from CSS photocopied zine effect by Lynn Fisher (@lynnandtonic). Public CodePen, MIT License.
Copyright (c) 2020 Lynn Fisher https://codepen.io/lynnandtonic/pen/YzwVJYp Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Desktop pencil treatment adapted from 3D CSS Pencil by FabioG (@FabioG). Public CodePen, MIT License.
Copyright (c) FabioG https://codepen.io/FabioG/pen/YyQrWY Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Pencil ferrule and eraser adapted from 3D CSS Pencil by Brad Arnett (@bradarnett). Public CodePen, MIT License.
Copyright (c) Brad Arnett https://codepen.io/bradarnett/pen/XyZKaG Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Gradient themes use ShaderGradient (@shadergradient/react), Copyright (c) ruucm, MIT License.
Sketch-style board rendering uses Rough.js, Copyright (c) Preet Shihn, MIT License.
Rough-mode glyph outlines are traced with image-vectorizer, a JavaScript port of Potrace by Peter Selinger. Licensed under the GNU General Public License, version 2. Corresponding source is available from those projects. The GPL-2.0 text is at gnu.org.