License and credits

The short version

You can reuse almost everything on FreeChessTrainer. The written content is open under Creative Commons, the code is open under MIT, and the puzzles come from a public-domain database. The only things we keep for ourselves are the FreeChessTrainer name and logo, so nobody can pass their own site off as ours.

Can I reuse the guides and FAQs?

Yes. The text we write, such as trainer guides, tips, FAQs and the About page, is shared under the Creative Commons Attribution-ShareAlike 4.0 license. A chess teacher can print a guide for a class, a club can quote our tips in its newsletter, and a blogger can translate a page. To do that, please:

• Credit FreeChessTrainer by name.
• Link back to the page you used, for example Chess Coordinate Training.
• Say if you changed the text.
• Share your version under the same CC BY-SA 4.0 license.

Can I use the board code and pieces?

Yes. The chessboard, the drills and the flat piece set you see on every board were made for FreeChessTrainer. Their code and drawings are released under the MIT license: you can use, copy, change and share them, including in commercial projects, as long as you keep the copyright and license notice. The software comes without warranty, as our terms of use explain.

Puzzles: the Lichess puzzle database

Every position in Chess Mate in One comes from the Lichess puzzle database, a collection of millions of puzzles taken from real games played on Lichess. Lichess publishes it under CC0, which places it in the public domain, so no credit is legally required. We give it anyway, because the database is the work of a free, open-source, non-profit chess server and its community.

We picked 450 popular mate-in-one puzzles across three levels and checked each one with chess.js, so every mating move counts as a correct answer. After you solve a puzzle, a link takes you to the same puzzle on Lichess, where you can see the game it came from. If you enjoy the puzzles, consider supporting Lichess.

Open-source software we use

FreeChessTrainer runs on free and open-source tools. Thank you to the people who build and maintain them:

• Astro builds the pages (MIT).
• Svelte powers the interactive boards and drills (MIT).
• chess.js checks moves and checkmates (BSD 2-Clause).
• Dexie saves your scores in your own browser (Apache 2.0).
• Tailwind CSS styles the site (MIT).
• Lucide draws the small flip and settings icons beside the board (ISC).

Fonts

The site uses three typefaces from Google Fonts: Archivo for headings, Poppins for text and DM Mono for numbers and coordinates. All three are released under the SIL Open Font License 1.1. We host copies on our own server, so your browser never contacts Google to load them, as described in our privacy policy.

Our name and logo

The FreeChessTrainer name and logo are not covered by the licenses above. You are welcome to mention us and link to us, of course. Just don’t use the name or logo in a way that makes people think we made, sponsor or approve your site, app or product.

Did we miss a credit?

If you made something we use and we forgot to credit you, or got a detail wrong, please write to [email protected]. We will fix it quickly. The same address works if you want to reuse our content in a way that the licenses above don’t cover.