Anki, Quizlet, Brainscape... I dislike all these overcomplicated flashcard apps. I just want the software equivalent of index cards, so I created [TSOFA - The Simple, Offline, Flashcard App](https://inventwithpython.com/tsofa/). It's exists entirely in a single HTML file you can view in the browser. You can edit the flashcards directly in the file, using just text or HTML tags. [Check out this demo.](https://inventwithpython.com/tsofa/tsofa.html) It also supports a CSV string for the flashcard content so you can import flashcards from other apps. Otherwise, it's just a simple, free flashcard app: No server, no ads, no registration, no premium features to pay for, no dependencies, no build process, no cloud sync. You can suggest improvements or report bugs on [the GitHub repo](https://github.com/asweigart/tsofa-the-simple-offline-flashc...).