CalmPlay

Install CalmPlay

On an iPhone or iPad, use Safari to add CalmPlay to your Home Screen:

  1. Tap the Share button.
  2. Choose “Add to Home Screen”.
  3. Turn on “Open as Web App”, then tap “Add”.
EN

Licenses and Acknowledgements

All games on CalmPlay are built in-house: Sudoku, 2048, Solitaire (Klondike), Minesweeper, and the chess interface were written from scratch for this website, including all artwork (card faces, pieces, glyphs, logo). The underlying game ideas are in the public domain.

2048 — acknowledgement. The game concept of 2048 was created by Gabriele Cirulli (2014), who released his original under the MIT license (github.com/gabrielecirulli/2048). Our version is an independent re-implementation with no code taken from the original; we credit it out of respect for the idea. The original 2048 is licensed as follows:

MIT License — Copyright (c) 2014 Gabriele Cirulli

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.

Chess engine: Stockfish (GPL-3.0)

The computer opponent in chess is Stockfish — a free, open-source chess engine. We ship the unmodified single-threaded “lite” WebAssembly build from the npm package stockfish@18.0.8 (upstream project: github.com/nmrugg/stockfish.js, the WASM port of official Stockfish):

Stockfish is licensed under the GNU General Public License v3.0. The complete, unmodified license text ships with this site: COPYING.txt. The engine runs as a separate program in an isolated Web Worker and communicates exclusively via the UCI text protocol.

Corresponding Source. The complete source code of the exact build we distribute is permanently available at the following address, pinned to the exact development state:

https://github.com/nmrugg/stockfish.js/archive/93c994592dcf3b4b21052ab925e9b534df9c0918.tar.gz

(Commit 93c994592dcf3b4b21052ab925e9b534df9c0918 — contains the full C++ source code and build scripts. The npm package itself contains only the pre-built program files and is not the source code.) Source-code questions: hello@calmplay.app.

Move validation: chess.js (BSD-2-Clause)

Chess move legality is checked by the chess.js library, version 1.4.0 (github.com/jhlywa/chess.js):

Copyright (c) 2025, Jeff Hlywa (jhlywa@gmail.com). All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The chess pieces and board are this website’s own designs.

Typefaces (SIL Open Font License 1.1)

Headings on this website are set in a self-hosted display typeface; body text uses your system’s fonts. No font is loaded from a third-party server. The display font is licensed under the SIL Open Font License, Version 1.1, and we ship its complete license text alongside the font file:

Website

Framework. This website is built with Astro (astro.build), released under the MIT license — © Astro contributors.

Analytics. No analytics or statistics service is used; this website loads no third-party scripts.

License questions: hello@calmplay.app

Noto Serif for Bulgarian

Bulgarian headings use Noto Serif 2.015 © 2022 The Noto Project Authors under the SIL Open Font License 1.1. It is self-hosted and loaded only on Bulgarian pages.