MemoCard

Spaced repetition works by showing a card at the moment you are about to forget it, and MemoCard implements that inside Telegram rather than as yet another app to install. Cards live in decks and folders, the schedule is calculated for you, and a daily notification brings back only what is due — which on most days is a five-minute session rather than an hour.

Two details set it apart from a plain quiz bot. Decks can be shared in Telegram with a link, so a teacher or a study group passes a set around without exporting files; and there is a catalogue of ready-made decks to start from when you would rather revise than type. Text-to-speech reads cards aloud, which matters for vocabulary, and a heatmap plus a streak counter carry the same motivation trick a habit tracker uses.

The project is open source under the MIT licence, runs in the browser and on phones as well as in Telegram, and its interface is translated into English, Russian, Ukrainian, Spanish, Portuguese, Arabic and Persian. The core is free; MemoCard Pro, $4 a month and payable with Telegram Stars or a bank card, lets you build and edit decks through ChatGPT — a whole deck from one request, fixes and examples for existing cards, IPA transcriptions, a copy of a deck in another language.