Comparison

memoryOS vs SkyWindow

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

SkyWindow

Features
Read full description

SkyWindow – Smart Planning for Astronomy & Astrophotography Many astronomy and astrophotography enthusiasts do not observe under perfect skies. Buildings, balconies, windows, and trees often limit the visible sky area. SkyWindow was designed exactly for these situations. SkyWindow helps you efficiently plan observations and astrophotography sessions based on your real visible sky window — ideal for smart telescopes and mobile observing setups. Whether you observe from a balcony, garden, rooftop window, or travel location, SkyWindow helps you determine when celestial objects become visible and worth capturing. Features • Tonight Quick access to the best observing opportunities for the current night, including visibility, timing, and sky conditions. • Catalogs Browse supported astronomy catalogs, inspect object details, and jump directly into observation planning. • Comet Hunter Plan observations for comets and asteroids with focus on motion, visibility, and timing. • Sites Manage observing locations such as balconies, gardens, windows, or remote travel sites. • Planner Build structured observation plans based on visibility windows, altitude, azimuth, and timing. • Mosaic Planner Prepare mosaic imaging projects for large deep-sky objects and advanced framing work. • Sky Journey Your personal observing journal with saved sessions, captured targets, favorites, retries, and observing history. Built for Modern Astronomy SkyWindow is designed for modern smart telescopes and efficient observation planning, especially for observers with limited sky visibility. Perfect for: • Smart telescopes • Balcony astronomy • Window observing • Mobile astrophotography • Travel observing • Deep-sky planning Plan smarter. Use your sky window efficiently. Explore the night sky with SkyWindow. SkyWindow is available in English, German, French, Spanish, Japanese, and Simplified Chinese.

Screenshots

memoryOS4 screens
SkyWindow4 screens

Verdict

The call

The clearest difference is price: memoryOS at Free against SkyWindow's $4.99. memoryOS also leads on chart position (#46 vs unranked) and iOS requirement (15.2 vs 26.2). SkyWindow's advantage is in-app purchases (none vs 28) and update cadence (every 5 days vs every 3 weeks). On ads 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

memoryOS is free to download; SkyWindow costs $4.99 up front. memoryOS sells 20 in-app purchases, starting at $3.99 per 7 days. SkyWindow asks for nothing beyond the download.

UpkeepUpdate frequency

memoryOS ships an update every 3 weeks, SkyWindow every 5 days. The most recent releases landed on October 2, 2026 and October 1, 2026 respectively.

Scorecard5 real differences · 6 level
memoryOS versus SkyWindow: the parameters behind the verdict, then further details
ParametermemoryOSSkyWindow
PriceFree — better$4.99
Rating4.9 (16K ratings) — better—
Positive reviews80.5% of reviews—
Number of ratings16K — better—
Update frequencyEvery 3 weeksEvery 5 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
Best chart rank#46 — better—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.2 — better26.2
Further details — not scored
Size248 MB19 MB
Age rating4+4+
DeveloperEncoder Inc.Dung Le

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

SkyWindow

Not enough reviews yet to summarise bugs or requests.

In-app purchases

20 purchases

memoryOS

Subscriptions17
  • Student Weekly Plan$3.997 Days
  • Student Monthly Plan7 Days trial$4.991 Month
  • Expert Weekly Plan7 Days trial$6.997 Days
Show 14 more
  • Essential Weekly Plan7 Days trial$6.997 Days
  • Essential Monthly Plan3 variants$14.991 Month
  • Essential Monthly Plan7 Days trial$14.991 Month
  • Student 3 Months Plan$19.993 Months
  • Expert Monthly Plan2 variants$24.991 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 Plan7 Days trial$149.991 Year
  • Expert Annual Plan1 Month trial2 variants$149.991 Year
One-time3
  • 10 Hearts$0.99
  • 10 Loci Coins$2.99
  • 50 Loci Coins$14.99
None

SkyWindow

No in-app purchases

Questions

Is memoryOS free?
memoryOS is free to download, with in-app purchases available.
Is SkyWindow free?
SkyWindow costs $4.99, with no in-app purchases.
Do memoryOS or SkyWindow have ads?
Neither memoryOS nor SkyWindow shows ads.
Which is updated more often, memoryOS or SkyWindow?
memoryOS ships an update every 3 weeks, and SkyWindow every 5 days. Most recently, memoryOS was updated on October 2, 2026 and SkyWindow on October 1, 2026.

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