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What is Koydo?
Koydo is a 15-million-card learning library that pairs every card with a unique bespoke visualisation — holofoil periodic tables, parallax-depth cells, 3D constellations, liquid-glass letters, animated piano notes, and six more styles. Cards span Sprouts (ages 2–5) through University (18+) across 21 subjects from math and language to philosophy and medicine. Koydo Cortex schedules reviews using FSRS-6 spaced repetition tuned to each learner's mastery curve. Standards alignment is automatic: every card links to Cortex concepts that already map to CCSS, NGSS, IB, AP, A-Level, Matura, Abitur, ENEM, ACARA and CBSE. Free tier offers 100 cards a day; Plus ($6/mo) unlocks the full library; Pro ($15/mo) adds an AI tutor and family sharing.
Flashcards
Learn anything.
beautiful cards for every subject.
Every card is beautifully designed for its topic — and smart spaced repetition brings it back the moment before you’d forget.
Free forever · 100 cards a day · no card required
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.
Holofoil
Periodic-table tilt-foil. Chemistry & elements.
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3D Parallax
Depth-layered scenes. Biology cells, ecosystems.
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Liquid Glass
Big-letter phonics for early readers.
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Constellation
3D rotating star maps for astronomy.
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Voice Bloom
Math and quizzes that respond with sound and touch.
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Cinemagraph
Looping piano cinemagraph for music theory.
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Origami Fold
Two-flap unfold for SEL + history events.
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Spinning Globe
Geography with pulse-pin landmarks.
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Crystal Lattice
Molecules + math concepts in 3D.
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Standards alignment
Common CoreNext Generation ScienceAPIB DiplomaA-LevelMaturaAbiturENEMACARACBSE
Free forever. Pro $5.99/mo. Founders Lifetime $75.
Start free and study as much as you like. Upgrade for unlimited cards, offline study, your own AI tutor, and family sharing — at a price that's easy to love.
See full pricingFrequently asked
- How many flashcards are there?
- Deep coverage across 6 age tiers (Sprouts ages 2-5 through University 18+) and every subject — plus drill decks that generate as much practice as you need, 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.
What is Koydo?
Start studying free in 30 seconds.
Browse 15 million cards. Start with the free tier. Upgrade any time.