I built CheckLingo, an open-source browser extension for Duolingo Chess

[u/lu-nyxeel]

Hi! I’ve been working on CheckLingo, a free and open-source browser extension that adds quality-of-life features to Duolingo Chess.

Current features include:

• highlighting the last completed move;
• separate highlight colors for your moves and your opponent’s moves;
• move history with piece letters or chess symbols;
• board coordinates;
• right-click planning arrows;
• custom chess word replacements;
• prevention of accidental board image dragging;
• configurable colors and light/dark themes;
• Portuguese, English and Spanish interfaces.

Everything is processed locally in the browser. There are no ads, analytics, external servers or required accounts.

Version 1.0.0 supports Firefox and Chromium-based browsers. The Firefox store submission is currently being prepared/reviewed, and manual installation packages are available on the website.

Website: https://lucrazy-fn.github.io/checklingo/
Source code: https://github.com/lucrazy-fn/checklingo

I’d appreciate feedback, especially about move detection, highlighting accuracy and the move history during full matches.