Comparison

Cogni vs FlashStacks

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

Head to head
About

Cogni

Create and study flashcards to master new materials efficiently. Utilize an enhanced spaced repetition algorithm to optimize study sessions for exams, languages, or complex subjects. Millions trust this method to achieve their learning goals.

Highlights
  • Create and review custom flashcards
  • Spaced repetition algorithm
  • Pre-made deck library
  • AI-enhanced recall
  • Progress tracking
  • Offline access
Read full description

Cogni empowers you to master new materials effortlessly by creating and studying flashcards. Built on an enhanced spaced repetition algorithm, the app optimizes your study sessions, ensuring you get the most out of your learning. Whether preparing for exams, studying languages, or mastering complex subjects, millions trust flashcards to achieve their goals. Start your journey to mastery today—no limits, no boundaries, just learning! - Languages - Medicine (MCAT, USMLE & More) - Anatomy & Physiology - Exam preparation (SAT, GRE & More) - Math - Law - Geography - Computing - And many more! Key Benefits: - Easily create and review flashcards tailored to your learning needs. - Customize your cards with colors, lists, and more to fit your style. - Access a massive library of pre-made decks to jumpstart your learning. - Review lecture materials and prep for exams with powerful spaced repetition. Thousands of students boost their grades with this science-backed approach. - AI-enhanced spaced repetition (SRS) for optimal recall. - Flexible study interface with swipe and tap actions for efficient learning. - Detailed statistics and progress tracking to monitor your success. - Offline access to study with media-supported flashcards. Get started with Cogni today and take control of your learning journey! Terms of Use: https://cogni.cards/terms/ Privacy Policy: https://cogni.cards/privacy/

About

FlashStacks

Transform study materials into interactive Home Screen widgets. AI generates flashcards from PDFs, and spaced repetition optimizes learning. Visualize concepts with image occlusion and track progress with detailed stats.

Highlights
  • Home and Lock Screen widgets
  • AI-powered PDF to flashcard generation
  • Spaced repetition learning
  • Image occlusion cards
  • Progress tracking and stats
  • Customizable widget themes
Features
Read full description

Your flashcards, on your Home Screen. FlashStacks turns your study cards into Home Screen, Lock Screen and StandBy widgets. Glance at a question between classes. Tap to reveal the answer. Tap again for the next card — all without opening the app. Learning fits into the moments already filling your day. ALWAYS VISIBLE, ALWAYS READY Widgets come in every size and rotate through your stacks automatically, so every time you pick up your phone there's something new to learn. Start a study session and your card follows you to the Lock Screen and Dynamic Island as a Live Activity. AI DECKS FROM YOUR NOTES Upload any PDF — lecture slides, textbook chapters, study guides — and AI builds a complete deck in seconds. Choose High-Yield for exam prep or Comprehensive for full coverage. FlashStacks even finds the diagrams in your PDF so you can turn them into image occlusion cards. LEARN A LANGUAGE FlashStacks Learn gives you ready-made packs in French, Spanish, Japanese, Korean and Mandarin — greetings, numbers, food, travel and more. Add a pack and pick up new words from your Lock Screen all day. SPACED REPETITION THAT WORKS FlashStacks uses the same proven science behind Anki. Cards you struggle with come back sooner. Cards you've mastered fade into the background. Study smarter, not longer. IMAGE OCCLUSION CARDS Add any image — diagrams, anatomy, maps — and draw boxes over the parts to hide. Tap to reveal what's underneath. Perfect for visual subjects. BRING YOUR CARDS WITH YOU Import from Anki, CSV, TSV or JSON. Search every card across all your stacks and keep them organised with tags. BEAUTIFUL BY DESIGN Every stack gets its own colour palette — soft pastels or bold modern tones — and your widgets match. Dark mode uses pure OLED black. TRACK YOUR PROGRESS See mastery, difficulty breakdown and 14-day activity for every stack, plus a study calendar across everything you've learned. Build a streak. Hit your daily goal. FLASHSTACKS PREMIUM Unlock unlimited stacks, AI deck generation from PDF, image occlusion cards and every FlashStacks Learn pack. Free accounts include up to 2 stacks. Monthly and annual plans available. Annual plans include a discounted first month. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Cogni4 screens
FlashStacks4 screens

Verdict

The call

Cogni and FlashStacks both sit at 4.7 stars, but that hides the real split: 100% of FlashStacks's written reviews are positive against 36% of Cogni's. Cogni's advantage is ratings volume (1.7K vs 7). On price, rating, update cadence and ads 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. Cogni sells 9 in-app purchases, starting at $4.99 per month and FlashStacks sells 3 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.7 for Cogni against 4.6 for FlashStacks. That said, the two scores are not equally well evidenced: Cogni has 1.7K ratings behind it against 7, so its average is the more settled of the two. Written reviews are what separate them: 36% of Cogni's written reviews are positive against 100% of FlashStacks's.

UpkeepUpdate frequency

Cogni ships an update every 10 days, FlashStacks every 8 days. The most recent releases landed on October 27, 2026 and October 25, 2026 respectively.

Scorecard2 real differences · 8 level
Cogni versus FlashStacks: the parameters behind the verdict, then further details
ParameterCogniFlashStacks
PriceFreeFree
Rating4.7 (1.7K ratings) — better4.6 (7 ratings)
Positive reviews35.7% of reviews100.0% of reviews — better
Number of ratings1.7K — better7
Update frequencyEvery 10 daysEvery 8 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFreemium
DevicesiPhone, iPad — betteriPhone
Requires iOS16.4 — better17.6
Further details — not scored
Size68 MB11 MB
Age rating4+4+
DeveloperCOGNIFLY LTDBailey Skewes

Customer experience

Cogni

All ratings1,684 ratings
Positive92.9%
Neutral2.7%
Negative4.4%
Written reviews199 reviews
Positive35.7%
Neutral17.6%
Negative46.7%

FlashStacks

All ratings7 ratings
Positive85.7%
Neutral0.0%
Negative14.3%
Written reviews5 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Cogni

Reported bugs

2 issues
  • App no longer available after paying for annual subscription
  • Occasional crashes

Requested features

4 requests
  • Integrate ChatGPT or Claude for automatic card creation
  • Add sub-decks for larger decks that need more review
  • Improve algorithm for hard/again ratings to better target struggling cards
  • Add subsections for decks to study different sections separately

FlashStacks

Not enough reviews yet to summarise bugs or requests.

In-app purchases

9 purchases

Cogni

Subscriptions7
  • Premium Monthly$4.991 Month
  • Premium Monthly$7.991 Month
  • Premium Monthly$14.991 Month
Show 4 more
  • Premium Annual$19.991 Year
  • Premium Annual$24.991 Year
  • Premium Annual$29.991 Year
  • Premium Annual$49.991 Year
One-time2
  • Lifetime Premium$69.99
  • Premium Lifetime$99.99
3 purchases

FlashStacks

Subscriptions3
  • FlashStacks Premium — Monthly$4.991 Month
  • Premium Special Offer$24.991 Year
  • FlashStacks Premium — Annual1 Month trial$39.991 Year

Questions

Is Cogni free?
Cogni is free to download, with in-app purchases available.
Is FlashStacks free?
FlashStacks is free to download, with in-app purchases available.
Which has better reviews, Cogni or FlashStacks?
Cogni is rated higher. Cogni averages 4.7 out of 5 from 1.7K ratings, while FlashStacks averages 4.6 from 7 ratings.
Do Cogni or FlashStacks have ads?
Neither Cogni nor FlashStacks shows ads.
Which is updated more often, Cogni or FlashStacks?
Cogni ships an update every 10 days, and FlashStacks every 8 days. Most recently, Cogni was updated on October 27, 2026 and FlashStacks on October 25, 2026.

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