Pentive

A free, open source, local-first, spaced repetition system that works offline, has p2p syncing, plugins, and first class support for collaboration. It's GitHub/Reddit for flashcards.

Plugins

Pentive's plugin system allows developers to directly modify the dependency injection container. Any UI component may be overwritten with a function that returns any DOM node. See example plugins.

YouTube demo:

Contributing

If you're technically inclined, see design decisions for a review of Pentive's architecture and design. Contributions welcome!