Comparison

memoryOS vs Blackjack Mastery 21 Trainer

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

Head to head
About

memoryOS

Enhance your memory and focus with interactive lessons and a virtual mind palace game. Learn scientifically proven techniques to improve knowledge retention and recall a wide range of information, from names and numbers to complex data and entire books.

Highlights
  • Interactive bite-sized lessons
  • Virtual Mind Palaces game
  • Spaced repetition system
  • Scientifically proven techniques
  • Improve knowledge retention
  • Memorize diverse information
Features
Read full description

memoryOS contains interactive bite-sized lessons by a 2X World Memory Champion and an educational 3D game of Virtual Mind Palaces - all in one easy-to-use app. It utilizes scientifically proven memory techniques, spaced repetition and patented game mechanics to enhance long-term memory storage and improve knowledge retention. memoryOS is loved by 500,000+ people worldwide because it is a whole new, joyful & game-changing tool for obtaining the most effective memorization skills. Co-founded by Jonas von Essen, who went from struggling to remember to becoming a World Memory Champion, winning on Who Wants To Be a Millionaire, "Jeopardy, and setting a world record by memorizing 100,000 decimals of Pi . memoryOS app has over 18k public worldwide ratings on Apple and Google app stores combined, averaging 4.8 stars. Users also continue adding 5-star reviews daily, sharing how effective and life-changing memoryOS has been for them. Also, memoryOS remains the most crowdfunded app in Kickstarter’s history. Memorization is as important as reading and writing and should be taught as our base skill. Our mission is to enable millions of people to remember needed information easily. With memoryOS, you will learn how to memorize: - Names, Long speeches, Lists of items, Birthdays, Personal facts, Passwords, Trivia, Languages, Vocabulary and phrases, Countries and Capitals, Flags, Historical timeline, Numbers, Periodic table - Content of complete books, Dates of significant events, Complex data structures, Concepts, and figures - Art, Anatomy, Decks of cards, Advanced number systems; Long sequences of numbers, Binary Digits You will also learn: - How to keep track of years, months, weeks, and days - Advanced study techniques, Spaced Repetition system, Speed memorization Why did Google Brands Accelerator recognize memoryOS as being 'Light Years Ahead' in the memory space? • memoryOS delivers results: During our pre-launch phase, thousands of users completed our demo and, on average, had a 70% increase in recall and a 60% increase in recall speed just after the first ~40min session. • Providing your mind with structured storage space: We have spent tens of thousands of hours creating and optimizing our Virtual Mind Palaces, so you don’t have to spend months constructing your own the hard way. These virtual palaces serve as blueprints for your mind's storage space, allowing you to easily encode, store and recall like a memory champion. • A proven innovative approach that works: During our research and development stage, thousands of people of all age groups and even those with difficult medical conditions found memoryOS as an effective and useful tool. Actual results exceeded our team’s expectations. • Gamified edtech at its best: memoryOS has proven to work on people with no prior gaming experience - anyone can use it. Utilizing the power of the Unity game engine, memoryOS is widely accessible on all mobile and tablet devices and is soon coming to VR. -- Joining memoryOS is free. This provides extensive value on the free plan, and you are not obligated to pay to start using it. You can subscribe to a Student Premium plan for as low as $3.49/month when billed annually or $4.99/month when billed monthly (it can be 10-20% higher in some countries due to local taxes). You can subscribe through the 'Shop' section of the memoryOS app and find the above-mentioned or go to your App Store app's profile and choose a desired plan there. Recurring payments will automatically renew unless you cancel your account at least 24 hours before the end of the current subscription period. You can manage your subscription, cancel anytime, or turn off auto-renewal by accessing your iTunes account. Join the memoryOS community of over 500,000+ early adopters who share this memorable journey! -- Terms: memoryOS.com/terms Privacy policy: memoryOS.com/privacy-policy Learn more at: memoryOS.com Contact us: support@memoryOS.com

About

Blackjack Mastery 21 Trainer

Features
Read full description

Blackjack Trainer Mastery 21 helps you learn how to play smarter, faster, and with confidence. Whether you're new to the game or want to practice basic strategy, this is the perfect tool to train your blackjack brain. -Real Hand Signals - Practice when to Hit, Stand, Split, Double, or Surrender -Built-In Strategy Chart – Access the Basic Strategy Table based on your selected house rules -Train Like a Pro – Build strong decision-making habits and increase your odds of winning -Get instant feedback on every move This app is perfect for beginners and players who want to improve their chances at the table. It helps you make the right decisions and understand the real strategies behind the game. Ready to take your Blackjack skills to the next level? Start training now with Blackjack Trainer Mastery 21.

Screenshots

memoryOS4 screens
Blackjack Mastery 21 Trainer4 screens

Verdict

The call

The clearest difference is ads: memoryOS at none against Blackjack Mastery 21 Trainer's shown. memoryOS also leads on chart position (#67 vs unranked). On price, update cadence, in-app purchases and device support 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. memoryOS sells 23 in-app purchases, starting at $3.99 per 7 days and Blackjack Mastery 21 Trainer sells 4 in-app purchases, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

memoryOS ships an update every 2 weeks, Blackjack Mastery 21 Trainer every 3 weeks. The most recent releases landed on October 26, 2026 and October 11, 2026 respectively.

Scorecard2 real differences · 9 level
memoryOS versus Blackjack Mastery 21 Trainer: the parameters behind the verdict, then further details
ParametermemoryOSBlackjack Mastery 21 Trainer
PriceFreeFree
Rating4.9 (17K ratings) — better—
Positive reviews80.3% of reviews—
Number of ratings17K — better—
Update frequencyEvery 2 weeks — betterEvery 3 weeks
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFree with in-app purchases—
Best chart rank#67 — better—
DevicesiPhone, iPad, iPod — betteriPhone, iPod
Requires iOS15.215.1 — better
Further details — not scored
Size231 MB44 MB
Age rating4+17+
DeveloperEncoder Inc.Anton Terekhov

Bugs and requests

memoryOS

Reported bugs

5 issues
  • Login issues and account management problems
  • Frequent crashes and app instability
  • Navigation and UI elements not working as expected
  • Syncing issues between devices and lost progress
  • Connectivity problems when using cellular data

Requested features

5 requests
  • More free content and lessons
  • Ability to create custom memory palaces
  • Better progress tracking and analytics
  • Integration with other learning/productivity apps
  • Offline mode for lessons and memory palaces

Blackjack Mastery 21 Trainer

Not enough reviews yet to summarise bugs or requests.

In-app purchases

23 purchases

memoryOS

Subscriptions20
  • Student Weekly Plan$3.997 Days
  • Student Monthly Plan7 Days trial$5.991 Month
  • Expert Weekly Plan7 Days trial$6.997 Days
Show 17 more
  • Essential Weekly Plan7 Days trial$6.997 Days
  • Essential Monthly Plan7 Days trial$14.991 Month
  • Essential Monthly Plan2 variants$14.991 Month
  • Essential Monthly Plan$16.991 Month
  • Student 3 Months Plan$19.993 Months
  • Expert Monthly Plan$24.991 Month
  • Expert Monthly Plan$29.991 Month
  • Expert 3 Months Plan7 Days trial$49.993 Months
  • Expert 3 Months Plan$69.993 Months
  • Expert 6 Months Plan7 Days trial$89.996 Months
  • Essential Annual Plan1 Month trial$89.991 Year
  • Essential Annual Plan7 Days trial3 variants$89.991 Year
  • Essential Annual Plan14 Days trial$89.991 Year
  • Expert Annual Plan7 Days trial$148.991 Year
  • Expert Annual Plan1 Month trial$149.991 Year
  • Expert Annual Plan7 Days trial$174.991 Year
  • Expert Annual Plan1 Month trial$174.991 Year
One-time3
  • 10 Hearts$0.99
  • 10 Loci Coins$2.99
  • 50 Loci Coins$14.99
4 purchases

Blackjack Mastery 21 Trainer

Subscriptions3
  • Premium Access$9.991 Month
  • Premium Access1 Year trial$39.991 Year
  • Premium Access7 Days trial$39.991 Year
One-time1
  • Premium Access$99.99

Questions

Is memoryOS free?
memoryOS is free to download, with in-app purchases available.
Is Blackjack Mastery 21 Trainer free?
Blackjack Mastery 21 Trainer is free to download, with in-app purchases available.
Do memoryOS or Blackjack Mastery 21 Trainer have ads?
Blackjack Mastery 21 Trainer shows ads; memoryOS does not.
Which is updated more often, memoryOS or Blackjack Mastery 21 Trainer?
memoryOS ships an update every 2 weeks, and Blackjack Mastery 21 Trainer every 3 weeks. Most recently, memoryOS was updated on October 26, 2026 and Blackjack Mastery 21 Trainer on October 11, 2026.

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