Comparison

Duolingo vs Optimem

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Duolingo

Learn languages, math, music, and chess through fun, bite-sized lessons. Build vocabulary, grammar, and real-world skills with a science-based methodology. Track progress and stay motivated with a global community.

Highlights
  • Bite-sized language lessons
  • Speaking, reading, listening, writing practice
  • Math skills development
  • Music reading and playing
  • Chess strategy and gameplay
  • Progress tracking and rewards
Features
Read full description

Learn a new language, chess & more with the world's most downloaded education app! Duolingo is the fun, free app for learning 40+ languages through quick, bite-sized lessons. Practice speaking, reading, listening & writing to build your vocabulary & grammar skills. Designed by learning experts & loved by hundreds of millions worldwide, our lessons make learning effective & fun and help you prepare for real conversations in Spanish, French, Japanese, Korean, Chinese, Italian, German, English and more. And now, you can learn CHESS on Duolingo! Whether you're a total beginner or looking to level up your game, you'll love learning chess the Duolingo way. Play matches and fun chess lessons for all levels, no matter the language - chess, ajedrez, xadrez, schach, Шахматы, الشطرنج. • Chess: Learn the moves, level up your game & play matches in our Chess course. Learn the basics, solve fun chess puzzles & improve your strategy with guided lessons. Whether you're new to chess or already play, our course is designed to help you have fun and build real skills. Checkmate! • Math: Forget lectures and math worksheets! Built by learning experts, our Math course makes math feel like a game. Boost learning and fight the summer slide with standards-aligned math lessons for elementary school, middle school, and high school students. • Music: Learn how to read music & play songs in our Music course, no instrument needed! Using an on-screen keyboard, you'll learn bit-by-bit. Whether you're learning a language for travel, school, career or your brain health, you'll love learning with Duolingo. Why Duolingo? • Duolingo is fun & effective. Game-like language lessons & fun characters help you build speaking, reading, listening, & writing skills, plus enjoy fun chess & competitive online chess in one app. • Duolingo works. Designed by learning experts, Duolingo has a science-based teaching methodology proven to foster long-term knowledge retention across language lessons & chess lessons alike. • Track your progress. Work toward your learning goals with playful rewards & achievements when you make practicing language lessons or chess online part of your daily habit. • Join millions of learners. Stay motivated with competitive Leaderboards as you learn languages & play chess online alongside our global community. • Every course is free. Learn Spanish, French, German, Italian, Russian, Portuguese, Turkish, Dutch, Irish, Danish, Swedish, Ukrainian, Esperanto, Polish, Greek, Hungarian, Norwegian, Hebrew, Welsh, Arabic, Latin, Hawaiian, Scottish Gaelic, Vietnamese, Korean, Japanese, English, & even High Valyrian! And now, learn Math, Music & improve your Chess skills with fun, bite-sized lessons. What the world is saying about Duolingo: "Far & away the best language-learning app." - The Wall Street Journal "This free app & website is among the most effective language-learning methods I've tried… lessons come in the form of brief challenges, speaking, translating, answering multiple-choice questions, that keep me coming back for more." - The New York Times "Duolingo may hold the secret to the future of education." - TIME Magazine "Duolingo is cheerful, lighthearted & fun." - Forbes "I Can't Stop Playing Duolingo Chess." - Wired If you like Duolingo, try Super Duolingo for 14 days free! Learn a language fast with no ads & get fun perks like Unlimited Energy & Monthly Streak Repair. If you choose to purchase Super Duolingo, payment will be charged to your Apple account, and your account will be charged for renewal within 24-hours prior to the end of the current period. Auto-renewal may be turned off at any time by going to your settings in the App Store after purchase. Any unused portion of a free trial period, if offered, will be forfeited when the user purchases a subscription to that publication, where applicable. Privacy Policy: https://www.duolingo.com/privacy Terms of Service: https://www.duolingo.com/terms

About

Optimem

Master any subject quickly with science-backed flashcards. Learn in short, engaging sessions using spaced repetition and multimedia support. Track your progress and customize your study experience with a simple, distraction-free interface.

Highlights
  • Bite-sized learning sessions
  • Spaced repetition system
  • Multimedia flashcard support
  • Progress tracking and stats
  • Customizable study settings
  • Dark mode
  • Content creation and sharing
Features
Read full description

Optimem helps you study & memorize any topic as fast as possible - Start learning in seconds. Choose from a wide variety of topics across Spanish, Music, Programming, and more. - Learn in 1-2 minute bite-sized sessions, like while waiting in line or on a bus. Quickly learn and practice on a fast path to mastery. - Experience simple, delightful design combined with cutting-edge scientific techniques. Together, learning can be more efficient and more enjoyable. Features - Freely and instantly download learning materials in the app from a wide variety of subjects - Seamless feed of questions to make learning fast and easy - Spaced repetition system (also known as SRS or Leitner system) which lets you spend less time learning - Sound and haptics feedback (short vibrations) to reinforce correct and incorrect answers - Confetti blasts on correct answer streaks for more delight - Support for images, audio, text, emojis and markdown formatting for flash cards - Support for text-to-speech for pronunciation and listening practice - Stats about your learning progress and rate - List and explore all cards in a topic - Customize new and review questions per day - Dark mode - Simple and distraction-free interface - Experimental and controversial Instant Brain Upload mode* - Connect and transfer content between your phone and another computer - Open source learning materials - Create, edit, remix, and share any learning materials Languages: - Spanish - French - Japanese – Hiragana & Katakana - Hindi – Devanagari alphabet - Russian – Cyrillic alphabet - Korean – Hangul alphabet - Mandarin Chinese - Norwegian - International morse code - Braille - American sign language - Toki Pona – a language with only ~120 words, designed to be simple and positive Other topics: - Piano keys - Music theory – music intervals & modes - Rust programming language - How to count in binary - … and growing! Learning materials can be created, edited, and shared by anyone. Brought to you by Organic Software. Privacy Policy: - https://optimem.org/privacy Have feedback or questions? - Contact us via https://optimem.org/discord

Screenshots

Duolingo4 screens
Optimem4 screens

Verdict

The call

The clearest difference is in-app purchases: Optimem at none against Duolingo's 28. Optimem also leads on ads (none vs shown) and review sentiment (80% vs 65%). Duolingo's advantage is ratings volume (5.5M vs 30) and update cadence (weekly vs monthly). On price, rating, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Duolingo sells 16 in-app purchases, starting at $9.99 per month. Optimem asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.7 for Duolingo against 4.7 for Optimem. That said, the two scores are not equally well evidenced: Duolingo has 5.5M ratings behind it against 30, so its average is the more settled of the two. Written reviews are what separate them: 65% of Duolingo's written reviews are positive against 80% of Optimem's.

UpkeepUpdate frequency

Duolingo ships an update weekly, Optimem monthly. The most recent releases landed on September 25, 2026 and September 17, 2026 respectively.

Scorecard7 real differences · 4 level
Duolingo versus Optimem: the parameters behind the verdict, then further details
ParameterDuolingoOptimem
PriceFreeFree
Rating4.7 (5.5M ratings)4.7 (30 ratings)
Positive reviews64.6% of reviews80.0% of reviews — better
Number of ratings5.5M — better30
Update frequencyWeekly — betterMonthly
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
Best chart rank#1 — better—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.016.0 — better
Further details — not scored
Size489 MB54 MB
Age rating4+4+
DeveloperDuolingo, IncOrganic Software LLC

Customer experience

Duolingo

All ratings5,464,639 ratings
Positive94.2%
Neutral2.4%
Negative3.4%
Written reviews29,453 reviews
Positive64.6%
Neutral9.6%
Negative25.7%

Optimem

All ratings30 ratings
Positive93.3%
Neutral0.0%
Negative6.7%
Written reviews20 reviews
Positive80.0%
Neutral10.0%
Negative10.0%

Bugs and requests

Duolingo

Reported bugs

3 issues
  • Freezing or crashing during lessons
  • Incorrect translations or answers marked wrong
  • Inconsistent behavior of certain features like leagues

Requested features

5 requests
  • Add more languages, especially less common ones
  • Improve grammar lessons and explanations
  • Allow more flexibility in navigating the course content
  • Provide better feedback and corrections for mistakes
  • Sync progress and features consistently across app and web

Optimem

Not enough reviews yet to summarise bugs or requests.

In-app purchases

16 purchases

Duolingo

Subscriptions10
  • Super Duolingo7 Days trial$9.991 Month
  • Super Duolingo7 Days trial$12.991 Month
  • Super Duolingo14 Days trial$12.991 Month
Show 7 more
  • Super Duolingo2 variants$59.991 Year
  • Super Duolingo14 Days trial2 variants$79.991 Year
  • Super Duolingo14 Days trial4 variants$83.991 Year
  • Super Duolingo7 Days trial$83.991 Year
  • Super Duolingo7 Days trial4 variants$95.991 Year
  • Super Duolingo1 Month trial$119.991 Year
  • Super Duolingo7 Days trial$119.991 Year
One-time6
  • Chest of Gems$0.99
  • Barrel of Gems (1200)$4.99
  • Chest of Gems (1200)$4.99
Show 3 more
  • Cart of Gems (3000)$9.99
  • Barrel of Gems (3000)$9.99
  • Cart of Gems (6500)$19.99
None

Optimem

No in-app purchases

Questions

Is Duolingo free?
Duolingo is free to download, with in-app purchases available.
Is Optimem free?
Optimem is free to download, with no in-app purchases.
Which has better reviews, Duolingo or Optimem?
Duolingo and Optimem are both rated 4.7 out of 5 on the App Store, from 5.5M and 30 ratings respectively.
Do Duolingo or Optimem have ads?
Duolingo shows ads; Optimem does not.
Which is updated more often, Duolingo or Optimem?
Duolingo ships an update weekly, and Optimem monthly. Most recently, Duolingo was updated on September 25, 2026 and Optimem on September 17, 2026.

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