Learn anything.
15 million+ beautiful cards.

9 bespoke styles

A card style for every subject.

Plain text cards are forgettable. Ours give every concept its own visual language, so it sticks.

Frequently asked

How many flashcards are there?

15 million+ cards across 6 age tiers (Sprouts ages 2-5 through University 18+) and 21 subjects — with deep coverage in every subject and tier, so there's a deck waiting whatever you're studying.

Where does the content come from?

Every card comes from a trusted, openly licensed source — including Wikidata, OpenStax, Tatoeba, Wiktionary, PubChem, community shared decks, and Koydo's own authored material — and the source is credited right on the card.

Is the content really human-curated?

Yes. Every card is reviewed and credited to its source before you ever see it — nothing is bulk-generated. So you can study with confidence that what you're learning is accurate and trustworthy.

What's a 'bespoke visualization'?

Every card is beautifully designed for its topic. Chemistry cards shimmer like a holofoil periodic table, geography cards spin on a 3D globe, phonics cards glow in liquid glass — nine distinct styles, each matched to the subject so concepts stick.

How does the spaced repetition work?

Koydo's smart scheduling brings each card back right before you'd forget it. As a card gets easier, reviews spread further apart — so you spend your time on what you're about to lose, not what you already know.

Does it work offline?

Yes. Plus and Pro let you download decks for offline study, and your reviews sync automatically when you reconnect.

What about my data?

Koydo never sells learner data. Read the full Privacy Policy at koydo.app/legal/privacy.

Can teachers use it?

Absolutely. Koydo for Schools starts at $4 per seat per year with an admin dashboard and single sign-on. Reach our team at sales@koydo.app.