Show HN: I built FlipCards – a flashcard app with variations to improve learning

[felipefreitasa_]

Hi HN, I’m Felipe, a 9-5 developer aiming to become a full-time indie hacker. I struggled with flashcard apps that focus on decorating cards instead of learning concepts, so I built FlipCards to solve that problem.

What it does: FlipCards lets you:

- Create cards for any concept (math, language, coding, etc.) - Add multiple variations per card – the more variations, the better your understanding - Study smarter – the algorithm randomly selects variations so you can’t just memorize Q→A patterns

Why it’s different:

- Most apps use reverse cards (Q→A, A→Q). FlipCards uses variations to reinforce concepts in multiple contexts. - Powered by the SM2 spaced repetition algorithm, scientifically proven for long-term retention.

Pricing:

- Free – 1 deck, 3 cards, 1 study session - Annual – $20/year for unlimited decks and cards - Lifetime – $50 one-time for unlimited everything

I built FlipCards because I kept getting stuck decorating cards in other apps. Now I can create as many variations as I want, and the algorithm mixes them for me.

I’d love feedback from the HN community:

- Does this approach to flashcards make sense? - Would you use an app like this for learning?

Try it here: https://flipcardsapp.vercel.app

Thanks, Felipe

[owenpalmer]

My feedback as an Anki user:

1. The landing page and app UI is beautiful and fast, great work.

2. Never require signup for trying an app, especially for a Show HN.

3. I see the value in trying to prevent memorization of Q → A patterns, but creating cards takes time. Instead of making 1 card, I now need to make 3, that triples the amount of time spent. Additionally, why do variations need to be associated to a parent card? What's wrong with flattening your card structure?

4. The annual subscription price seems a little high, especially since there are so many free SRS programs out there.

5. Memorization of Q → A patterns can be mitigated by other means, such as making more open ended cards, requiring longer answers, or by simply trying not to just memorize and forcing yourself to think about the card and it's applications.

> Would you use an app like this for learning? Would I use it? Perhaps. Would I pay for it? No. Anki has so many more features, plugins, local control over my data, and... it's free.

[vunderba]

You have to associate variations as a single "owner card" otherwise you're adding in unnecessary reviews. You want to review 100 cards (which display a random variation on demand) not 500 cards. That's why you need to use a bit of Anki JS to randomize the "multiple fronts" on a single card to achieve the same results.

Source: This is what I do on my Anki decks

[mvieira38]

5- I don't know if that's even an issue that needs solving with Anki. If that ever becomes an issue with your deck it's probably because you don't add enough cards per day (or preferred time period) and enough cards per subject. I wrote about this in a comment last week I think, but a simple vocab card should actually be like at least 6: vocab <-> image (2), vocab <-> native vocab (2), vocab <-> write out native vocab (2). The text-based answers should still contain an image, too, for better embedding of the knowledge.

People that complain that Anki ends up being just Q -> A memorization are often using it superficially. And even then, won't the algorithm just phase the useless cards out anyways when they become too easy?

[jonwinstanley]

+1 for signup. I'd have defo signed up to try it out, but I don't use Google to sign in to anything I'm afraid

[HaroldPD]

Avoiding 'Decorating Cards' appears to be your unique selling point, as it is the most prominent headline text on your website and mentioned twice in your text here.

The meaning of this is obvious to you, while being obscure for me. Perhaps have a link within your site to expand on the meaning of 'Decorating Cards'. ( I assume it is prettifying. Perhaps it is initial card creation, or bulk loading. Perhaps it is includes other steps. ) Describe how your software is superior to putting minimal effort into using default anki cards with text and images.

[mvieira38]

OP is not a native English speaker and thought "decorar", the Brazilian Portuguese verb for memorize (with a "mindless memorization" subtext) translated to "decorate".

[charlie-83]

Hey Felipe, this looks really clean. I'll give you some first impressions I had and hope they ate useful.

What is this app on? Is it just a website or is it a mobile app? Is it going to work offline?

What does "decorating cards" mean? I haven't heard that term before but it seems to be a key part of your selling point.

Also, how does adding variations to a card in your app differ to just adding variations as new cards in another app?

The screenshot of the app could be a lot bigger (Firefox mobile). There's two layers of blank space around so I can't actually read the text without zooming.

"Most apps use reverse cards (Q->A, A->Q)" I don't understand what this means.

I like the pricing scheme. It's simple. The only thing I would change is to add rent to buy. E.g. if you pay 20 for a year and then decide you want lifetime it's only 30. This helps to avoid the situation where 50 is too much for someone when they aren't sure they'll keep using it but 20 feels like a bad deal if they end up using it a lot and get the lifetime anyway (they've "wasted" 20).

[mvieira38]

The idea is great, although I'm a little against the spirit of releasing this as a paid product instead of an Anki plugin/front-end or something. Alas, my biggest feedback is marketing stuff: the english on the landing page is way too broken for a premium paid product; I shouldn't need an account to try a simple app; this is surely not the ONLY (in all caps) app to do "variations". Maybe be more detailed on what the variations are and how it's different from the bajillion free Anki plugins out there.

[mvieira38]

Also, why SM2 instead of FSRS?

[bpev]

Probably simplicity. In my experience, SM2 has less levers, and is easier to implement initially.

[jarrett-ye]

SM2 has less parameters, but there is not a systematic way to tweak them correctly. With the optimizer, it's easy to make FSRS adaptive to any learners. There is only one lever for user to tweak in FSRS: the desired retention.

[joshdavham]

Out of curiosity, did you use an existing package for sm-2 or did you implement it from scratch?

I only ask because I've implemented various sm-2 packsges in Python, Typescript and Rust and have made them available under the MIT if anyone's interested: https://github.com/orgs/open-spaced-repetition/repositories?...

(Also, nerdy aside, but the original sm-2 technically had 6 possible ratings)

[komali2]

I'm happy for you that you've done this, but I don't understand why someone would pay for this instead of using Anki. Especially since chatgpt can generate anki decks for free.

[emursebrian]

Anki is great for what it is, but it has some annoyances when studying languages. They were annoying enough for me that I build some tools for Anki to try to address the problems. Eventually, I migrated my SQL scripts and JavaScript code to a lightweight .NET Core app that replaced Anki entirely.

This app was the starting point for presenting interactive content in Emurse. We're currently focusing on filling in areas of language learning that are missing - like phonetics.

If anyone is interested, they can checkout Dogen's Phonetics Course on Emurse: https://emurse.io/courses. There's also an "instant demo" for the Thai Course where you can try a demo without creating an account.

[kebsup]

Nice to see someone taking the concept of card variations to all concepts.

I'm taking this to extreme with Vocabuo[1] for language learning. For a single word, I have cloze cards, reverse cloze, definition cards, dialogs, audio and a few more.

At some point, I'd like to take the card type into account when calculating the next repetition stage, but that's a bit far into the future.

[1] https://vocabuo.com

[qwertytyyuu]

I’m still not quite sure what benefits this offers over anki

[rickcarlino]

Love the idea! Consider adding concrete examples of what a variation is on your landing page and making it very prominent.

I’ve been exploring a similar idea, feel free to reach out if you ever want to talk.

https://rickcarlino.com/notes/creating-micro-lessons-from-sp...

[ProofHouse]

I gotta say of all the flipcard apps I’ve looked at, at this point I don’t wanna create all my flip cards manually AI should Do it, and I’ve seen none that do. Sure the ability to do that and adjust but at this point, it should just be AI first. Let me put in the topic and refine it in my cards are set up for me on the top things I need to learn.

[Ey7NFZ3P0nzAe]

BTW I made and used my own reformulator script for anki cards. Every night the script would just find the failed cards of the day and reformulate them.

It's part of my AnkiAiUtils: https://github.com/thiswillbeyourgithub/AnkiAIUtils

[snitty]

Is this web only? Are there apps? Hard to sign up for something when I have no idea what I'm buying.

[willingo]

im working on a language learning app and have built a flash card feature as well.

lingodailynews.com lets users read the news in the language they want to learn at their reading level. it creates a vocab list and then you can practice with flash cards.

your approach looks cool but i didnt sign in the try it. you can test mine without creating an account. id love to hear some feedback

[vunderba]

Good job getting across the finish line. I do think the flashcard market (particularly subscription) is pretty competitive so bear that in mind.

Without an export option (which I didn't see listed in the features), you're going to have to convince people that your walled garden is worth the price of admission.

Related, I used to have a dedicated flashcard study application that could handle "card variations" but it was a hassle since the app was desktop only. With a bit of JS and custom card types, you can actually do this in Anki now which gives the benefit of dedicated mobile app, syncing, etc.

https://ankiweb.net/shared/info/163606663

I experimented with autogenerating variations of a single card using LLMs but at the end of the day, the best flashcard is probably the one you write yourself. (similar to mnemonics)

[guilamu]

I don't have a Google account. How do I register?

[emursebrian]

Multiple variations "per-card" are the way to go. It was one of my big gripes about Anki too! My other big complaint is that it only really is tracking one metric when it comes to study - whether you remember the "card" or not.

This is where Anki falls short for language study, because we as language learners also want to look at listening & reading comprehension as well as pronunciation.

Any reason why you're using SM-2 over FSRS? In Emurse we're using an algorithm similar to SM-2, mainly because FSRS wasn't out when we started building it. it works well enough because we've come up work arounds for Anki's problem of workload distribution. Looking into FSRS a bit, I am definitely interested in giving this a shot and seeing if it improves it in that area.

[vunderba]

To add another bit of feedback - it seems like a lot of people in the comments don't understand the value of variations so OP you'll want to show an actual case study example immediately.

Here is one to demonstrate:

  Variation 1:
  This famous escape-artist was born in 1874 and died in 1926.

  Variation 2:
  What famous magician born in 1874 passed away of peritonitis 52 years later?

  Answer: Harry Houdini   

Variations ARE the SAME CARD. They're just a means of "rephrasing" the question to break your brain from its ruthless pattern matching ability.

Answering any variation causes the next review time for THIS CONSOLIDATED CARD to get pushed back.

I achieve a similar variation system in my own flashcards but use javascript + Anki to accomplish it.