A simple browser extension for one-click analysis of Chess.com games on Lichess.
I love free, powerful open-source software! Chess.com does not offer free cloud analysis, only local line evaluations. The first is a lot easier to understand for beginners and much more accesible to users with lower end devices. Lichess cloud analysis is a wonderful tool, and users who might not want to leave chess.com (because of their friends or arguably better puzzles and lessons) can get a glimpse of its advantages.
This is a Chromiun-based extension, so you can use it on Chrome, Edge, Opera, Firefox, or other (non-tested) web explorers. Find it either on the Firefox Addons website or the Chrome Webstore.
Chrome Webstore
Link!
Firefox Addons
Pending review.
Manual installation
Depending on your browser and your OS, you have two options.
- (Any OS): Download and unzip source code, go to chrome://extensions/ or your browser's equivalent, turn on developer mode, click on "load unpacked", and go to the directory of the source code.
- (Easier, but only MacOS/Linux) Drag the latest .crx file from release from this repo and drop it in chrome://extensions/ or your web explorer's equivalent (make sure developer mode is enabled!).
After you have finished a game on chess.com or when you go to review a game, the script injects an HTML button under the nominal Analysis button. When clicked, it takes you to a Lichess analysis board of the same game.
Is there a game import limit?
Yes, Lichess limits import to 100 games per hour when not authenticated (OAuth2). The extension currently does not ask the user to authenticate in order to lessen set up time.
How does the extension work?
The script scraps your game's PNG from chess.com through the DOM and then sends a POST request to the Lichess API through the api/import endroute. Chess.com's official API is very limited, so getting information from the DOM directly is necessary; currently, there is no way to get a game's PGN through the API. If this ever changes, I will update the source code and the documentation to implement this better practice.
The extension uses Arrive.js, which abstracts the interface of mutation observers, to interact with the DOM efficiently.
