Flashcards by NKO is an iPhone-based application that provides an engaging educational solution for students and teachers worldwide. With over 2.5 million downloads, the app is widely used in classrooms and schools globally.

The app offers a Spaced Repetition System (SRS) that tracks your progress and keeps you organized. It allows users to create rich text formatted flashcards with pictures and download millions of flashcards on hundreds of subjects created by both experts and novices. The app also offers 16 studying/testing games such as Matching, Memory, True/False, Spelling, Words, Q-Battle, Flow, Flappy, Dig It Up, Ninja, 2048, Bingo, Q-Battle MP, Blocks, Letters, and Loci.

Flashcards by NKO has six built-in keyboards and supports custom keyboards. It provides a sophisticated class management system for teachers, including student folders for personalized learning, teacher messages, and statistics detailing who reviewed what, when, for how long, and what tools and games are used. The app also offers multiplayer games. Additionally, it has a full-fledged manual and slideshow mode, linear/adaptive/shuffle mode to enhance retention, and five tools like Review, Explore, Quiz, Listen, and Collage. The app is free and has no distracting ads.