Memory Hammer

Remember everything you want—forever!

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Inspiration

In the age of AI, we rely on instant answers instead of memory, which makes us more forgetful.

I built Memory Hammer 🧠🔨 to change that. With the help of AI, it can turn your study material, notes, photos, or even visual mnemonics into flashcards. Using spaced repetition, it helps you build the habit of recalling what truly matters—so you can remember it forever.

What it does

Memory Hammer is your AI-powered flashcard companion that makes memorization effortless and permanent. Using cutting-edge spaced repetition algorithms, it ensures you never forget what matters most.

KEY FEATURES:

🤖 AI-Powered Flashcard Creation

• Generate flashcards instantly from text or images

• Let AI create visual mnemonics for complex concepts

• Smart content extraction from any topic

🧠 Scientific Spaced Repetition

• FSRS algorithm optimizes review timing

• Learn more efficiently with less effort

• Adaptive scheduling based on your performance

📱 Seamless Experience

• Use single account on multiple devices

• Cloud sync keeps your progress safe

• Clean, intuitive interface

🎯 Smart Reminders

• Personalized review notifications

• Never miss a study session

• Build consistent learning habits

Whether you're a student preparing for exams, a professional learning new skills, or anyone who wants to remember more, Memory Hammer transforms forgetting into a thing of the past.

Start your journey to perfect memory today!

How we built it

Memory Hammer, RevenueCat, OneSignal - Epic Threeway Handshake

I've been contemplating and prototyping👩🏻‍🍳 Memory Hammer for over a year.

Shipaton by RevenueCat🐱 finally gave me the push to rapidly add more features, test and release it.

RevenueCat

Revenuecat paywall screenshot of both light and dark theme

RevenueCat’s paywall made it effortless to set up payments in Memory Hammer

The app comes with a 7-day free trial, giving users access to all three modes—Notes, Photos, and Visual Mnemonics—with some limits on the number of flashcards they can generate.

After the trial or if they want to generate more flashcards, users can easily upgrade to the premium plan by tapping the upgrade button in the limits widget or through the upgrade button in the account page.

RevenueCat paywall automatically adapts to the device theme and users can complete their purchase 💳 directly within the paywall. And just like that—ka-ching 💰—the payment lands in my bank 🏦.

OneSignal

screenshots showing OneSignal dynamic onboarding

OneSignal's customer engagement tools made it really easy to communicate with my users to help them make full use of Memory Hammer and reduce churn rate

  1. I used OneSignal In App Message(IAM) for dynamic on-boarding. I ask my users "Why do you want to improve your memory now?" and based on their answer I show them custom on-boarding screens to show how Memory Hammer can fulfill their needs. I store their answer in OneSignal as motivation user tag for re-engagement.

  2. I use OneSignal IAM to ask for notification permission.

  3. I use OneSignal IAM to display app update alert.

  4. I use OneSignal push notification REST API to send push notifications for review alerts from back-end.

  5. I store the following user tags in OneSignal from the app - email_opt_in, first_name, motivation, last_review_at, flashcard_saved_at .

  6. I have integrated Revenue Cat with OneSignal to send the following user tags - expiration_at, active_subscription, store, app_user_id, subscription_status .

  7. I have created several templates based on the different motivations of the Memory Hammer users for push notification, email and In App Message for use with Segments, Journeys and API.

  8. I have segmented users based on their motivation for using Memory Hammer like 'Want to improve test scores', 'Want to become smarter' and 'Want to be a superager'.

  9. I have created a strict 'Inactive Subscriptions' segment based only on the user tags - flashcard_saved_at and last_review_at timing.

    9.a) Strict 'Inactive Subscriptions' segment contains users who don't have flashcard_saved_at, last_review_at user tags (earlier users who didn't go through on-boarding) OR flashcard was saved 7 days ago OR flashcard was reviewed 2 days go respectively.

  10. I have created a strict 'Engaged Subscriptions' segment based only on the user tags - flashcard_saved_at and last_review_at timing.

    10.a) Strict 'Engaged Subscriptions' segment contains users who saved their flashcard in last 7 days OR flashcard was reviewed in last 2 days. This is determined using flashcard_saved_at and last_review_at user tags respectively.

  11. I have created different Journeys for aggressive re-engagement with inactive users based on their motivation and use the aforementioned templates for communicating with them. These journeys are aggressive because if the users don't review their flashcards on time in Memory Hammer, their progress will be lost. Using the fun Memory Hammer mascot - Hammer in the OneSignal templates, I'm nudging the users to continue their streak without irritating them.

    11.a) Journey for re-engaging users who use Memory Hammer for improving test scores will get push notifications and emails like - 'You can score more in your tests' , 'You can still score more' and 'You are going to score less' in order. Between the push notification and the email there is a 2 day wait period.

    11.b) Journey for re-engaging users who use Memory Hammer for getting smarter will get push notifications and emails like - 'You can become smarter' , 'You can become even smarter' and 'You're going to be dumb' in order. Between the push notification and the email there is a 2 day wait period.

    11.c) Journey for re-engaging users who use Memory Hammer for retaining memory when they age will get push notifications and emails like - 'Don't loose your memory' , 'You can do it' and 'You're going to forget everything' in order. Between the push notification and the email there is a 2 day wait period.

  12. I have created on-boarding journey to send dynamic welcome messages based on the motivation of the user (currently archived as growth plan is limited to 3 journeys).

  13. I have created an IAM to get the user motivation of users from older versions of Memory Hammer (Before the dynamic on-boarding version was released). I will be releasing this as update in the next version of the app (0.2.7).

Note: Screenshots of OneSignal push notifications, In App Message and Emails are included in the images section.

Challenges we ran into

  • I didn't know about Shipaton before the beginning of the contest so even though I've been ideating and prototyping Memory Hammer for a year the actual build took place after August 1st. So I had to build, iterate, release to market, promote in loop within the hackathon time-frame.

  • I had to postpone the iOS release to after the hackathon as I wanted to focus on improving Memory Hammer in Android and get user feedback than juggling between two platforms.

Tough Choice meme with Memory Hammer label, Add more features in one button and promote existing features in another button

  • Biggest challenge of all was deciding between building new features and promoting existing features.

Accomplishments that we're proud of

  • Built and released Memory Hammer within the stipulated period of the hackathon and grew it to 3000+ installs and 2000+ users within 3 weeks.

2000+ happy users, 5 stars, A happy hammer with its arms up in air

  • Now that the trial plan of the initial set of users are starting to end, some of them are starting to purchase the premium plan

honest work meme showing revenuecat subscriptions

What we learned

  • How simple it is to collect payments in app by integrating RevenueCat paywalls.
  • How automating communications and re-engagement with the users using OneSignal can help grow my app.
  • Building an app need not be a lonely secluded affair, sharing what we do in public can help create audience for the product and get valuable feedback. I learnt to become comfortable before camera shooting short videos of my progress with memory hammer and sharing it on social media.

What's next for Memory Hammer

  • Leaderboard for creating incentives for the users to review flashcards regularly.
  • iOS release of Memory Hammer.

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