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Show HN: I combined spaced repetition with emails so you can remember anything (ginkgonotes.com)

244 points by iskrataa ↗ HN
Hey HN,

I am a student shipping apps in my free time. This is my 4th for the year!

Non-fic books and podcasts have been part of my life for years now but I always struggled with remembering what I’ve read or listened to. I wanted it to stick even after years.

My notes list grew large but I never really revisited them. That’s why I created GinkgoNotes.

You can enter notes you want to recall and leave it to the app to create a personalised (based on spaced repetition) email schedule. That means you’ll get your notes emailed to you a couple of times exactly when you should read them again (based on Ebbinghaus's Forgetting Curve) so it’s certain that you’ll remember them.

I hope this will be helpful as it was for me. Would love some feedback!

Iskren

97 comments

[ 3.7 ms ] story [ 180 ms ] thread
gravity2060
This is so cool and something I’ve wanted for a long time, but it isn’t quite right yet (for what I personally want in an app like this.)

I am your target market, and I’d buy the lifetime /annual sub in a second if it had these features:

I want control of the SR sequence or, I want to know what SR algo you are using and know it is best practice model. The landing page says 4 sends, but that isn’t true SR.

The next thing, I’d want to see all of my “cards” or information pieces when I am logged in, so I can see and edit and delete and keep the database clean with a total view of content. The next thing I’d need (maybe you have this?) is for the email to effectively be a flash card, where the email content is the front and a link the email takes me to the “back” of the card so I can’t use cloze delete and other techniques. The last thing is bulk upload of content via a csv so I can bulk import mochi /anki / llm generated content.

I wish you luck with this and would (selfishly) encourage you to not ship so many different things, and instead encourage you to pick one and make it best in class for niche users like me who would spend and spend on premium solutions, but won’t spend on superficial implementations.

iskrataa
Can't thank you enough for the feedback. These are all great ideas which I'll look into.

I was wondering what is your experience with Anki? Are there reasons you are looking into alternatives or do you just like the idea of getting stuff by email? Thanks again!

latentsea
Why email at this point and not just Anki?
ozim
Not the person you asked - but for me it is that I check emails compulsively any other app I have to remember/tend to forget. Like Todoist is great but I can go weeks without opening it and I skip tasks because of it unless I set email notifications.
latentsea
Hmm. SRS is a daily commitment though. If you skip it the reviews just pile up, which tends to be painful enough that you quickly learn it's a daily commitment. I couldn't imagine getting 150 emails a day to review stuff, or that being a workable UX.
ozim
I think 10-20 flashcards a day is better than 0. But on the other hand it might not be rate to learn something quickly enough.
latentsea
With the original Anki algorithm the rule of thumb is your daily review load will be 5x your rate of new cards per day. So 10 to 20 reviews per day is between 2 to 4 new cards per day. Definitely not enough for language learning, which is my use-case, but may be ok for certain other things.
e12e
> 2 to 4 new cards per day. Definitely not enough for language learning

What is your expected rate of acquisition for a new language?

40*365 ~ 14 000 new cards a year - that's a ten thousand word vocabulary with four thousand cards to spare for grammar, idioms etc?

latentsea
When I learned Japanese around 15 years ago I did 10k in one year. Was a great pace. Still speak it to this day, so it worked like a charm.

I try to target 35 a day, and expect to hit that at least 80% of the time.

wellthisisgreat
Hey not to distract from OPs post, but I wanted to get into SR for a while, and your "what is your algo" question aligns with my line of thinking when approaching new methodology.

Could you please share your SR tech stack? Are there good apps etc., that can make the process a bit easier? The pen-and-paper approach I used in uni for learning kanji / new languages has scarred me somewhat, so I am eager to try something tech-heavy.

safety1st
On the topic of SR specifically, what does it mean to be best in class? I am just a layperson who uses a SR tool or two and has a passing interest in the topic, but the Wikipedia article on SR gives the impression that there are a variety of algorithms out there and none are established by research to be definitively better than the others, in fact the Criticism section mentions a study which found that absolute spacing was just as good. https://en.wikipedia.org/wiki/Spaced_repetition#Research_and...

The OP said he's using Ebbinghaus' "forgetting curve" which is not exactly a SR algorithm but something similar, there is an actual formula associated with it - https://en.wikipedia.org/wiki/Forgetting_curve

simple10
Congrats on the launch! I second the request for lifetime pricing option.

Also, the jump between $4/mo to $59/mo could use more explanation to justify the price gap.

It's worth considering listing GinkoNotes on AppSumo if you decide to offer a lifetime deal. I think it would do extremely well.

iskrataa
Hey, there is a lifetime option and it's just the higher number you mentioned.

I suppose it's not immediately obvious that it's a one-off purchase, so I'll be working on the design aspect of this.

Thanks for your interest and suggestions!

TripleChecker
Neat idea! I might consider pushing a free trial more since this feels like the type of product someone could begin to rely on and then be more likely to upgrade. A few positive testimonials wouldn't hurt.

A couple minor link fixes on your homepage, see here: https://triplechecker.com/s/230357/ginkgonotes.com.

1) Blog on footer is broken link 2) Affiliates on footer doesn't take you anywhere

iskrataa
Yes, I agree with both statements. Although I'm just starting and don't have any testimonials yet, I was thinking of sending an email to users requesting testimonials in exchange for the premium plan.

Just fixed the footer, nice catch! Shipping fast comes with some faulty copy pastes I guess...

wrboyce
Very interesting concept! I was about to dive right in when a voice in my head reminded me that my inbox discipline is terrible and I don’t need even more automated emails that will serve only to increase my unread count (which currently stands at 16878 in my Personal inbox).

Have you considered expanding this to notify via other mediums such as iMessage (if possible, this would be my preference) or the presumably easier WhatsApp/Telegram (the Telegram Bot API is pretty great, I’d imagine would be very easy)?

I’d also echo the free trial sentiment expressed elsewhere in the comments, take the mythical drug dealer approach and get ‘em hooked on freebies!

iskrataa
Yes, that's definitely a major drawback for people who are not so active via email (or got their inboxes spammed by marketing haha).

Will explore some options with the messaging apps, thank you! Do you think at this point it's not easier to open a specific app for that or there's a reason you prefer it to be via a messaging app?

andai
Getting messaged is different from opening Anki, which I often avoid for months at a time. I imagine I'd be much more likely to respond to a notification just because of how strong of a habit that is.
wrboyce
I feel like writing a specific app is not only more effort on your part but easier to ignore on mine (and more friction, a lot of people are hesitant to install new apps).

Personally I'm a big iMessage/Telegram user and as such unlikely to leave things unread on those mediums (they're one of the few apps that I allow to push notifications and display an "unread" badge); my reading of your post was that a selling point of GinkgoNotes is that it appears in already established workflows.

rahimnathwani
This is an interesting approach. Congrats on shipping!

I worry that it won't be effective. Systems like Supermemo and Anki work because of:

1) Spaced repetition (showing you the thing at the right time).

2) Retrieval practice (having your brain practice retrieving the thing you're about to forget).

3) Feedback and automation (using your self-rating to schedule the next review).

You are doing #1 and #3.

But you totally skip #2, because you show all the info in the email. So, unlike Anki, Supermemo or Quantum Country (which someone mentioned in another comment), there's no front/back or cloze deletion, and no retrieval practice happening.

Perhaps putting the question in the email subject and the answer in the email body would work?

iskrataa
Thanks for the feedback!

I agree, and this is something I thought about a lot during the design process. In my experience, just looking at the note (#1 in your example) helps a lot more than no repetitions (which is obvious of course), but it's still a huge improvement compared to my previous flow.

As for repetition, I was thinking of replying to the email with what you think is the answer and letting an LLM decide if you remember correctly. Is that something that sounds effective to you?

rahimnathwani 

  I was thinking of replying to the email with what you think is the answer and letting an LLM decide if you remember correctly. Is that something that sounds effective to you?
The nice thing about your tool is the simplicity and low-friction due to using email. For retrieval, replies might work, but I wonder whether the people who are willing to do that work are the same people who would just install Anki instead.
passwordreset
Email seems like a no-go here. It would feel like spam. If you wanted a something more conversational, I'd consider doing this over text messages.
85392_school
You can practice retrieving something without entering and checking it.
a3w
For Pete sake, don’t use an LLM.

Just use CSS to hide/show the answers, or a little bit of JavaScript for just that. Or scrolling, if it is text only. Or links to the answer an http server.

vineyardmike
Just create a “show answer” link.

The link can literally encode the answer in the URL, which you can just hide the raw url it in the emails’s HTML. (Fox examples, put it as base64 chars in query parameters)

Then you can host a (static) webpage that renders the text. This lets you host any users text w/o an interactive site. No live database, no ops burden, etc.

If you wanted to get fancy (which users of such a product probably would probably want) throw in “success/failure” links so your users can report the results and get changed frequency of spaced repetitions based on their success rate.

moojacob
I really like how you can create a note from the landing page. 1) it helped me understand how the app worked better than any screenshots or videos while 2) nudging me to sign up.
pugworthy
It seems you've made a digital mnemometer!
guluarte
I'm a big fan of SuperMemo16, if you could add incremental reading that would be great.
xkbarkar
I have 3 email in-boxes. One ancient rarely used since the early 2000, my personal daily email and my work email. Between then there are some 100k unread emails.

I am not the target audience for this service.

iskrataa
I think there are a lot of people like you, so I would definitely look into other ways of communicating. Thanks for the feedback!

If it was over WhatsApp, for example, would you be interested?

exe34
I do an annual amnesty, every email goes into archive on the first of January.
vundercind
I sometimes go most of a week without checking any email address. I’ve gone a month without looking at my personal one. It’s basically just for transactional mail, I don’t get things from people there.
Cotterzz
Interesting. I couldn't see myself using a tool like this for bulk remembering of things. And I don't think it would be practical for that. But for specifically important things like certain words my brain like to forget from time to time, numbers I need to remember or a very important hospital appointment, this could be very useful.
ianbutler
Email is the only thing I have conditioned myself to reliably check so this system probably has the best shot for me. Nice job, will try it out. Ive been meaning to make a real attempt at learning Japanese.
iskrataa
Thank you! Have fun learning Japanese!
wowsoleet
The idea is good but:

1) Paid model, $10 for an email on timer? Copilot, Spotify and Windsurf charge the same. Won't pay on principle THIS amount of money for a service which is done self-hosted in 30 minutes with ChatGPT, neither will a normie buy paid calendar, no offense. $1 is realistic, still you're gonna be profitable and much more scalable imo. Trial period of 2 weeks is mandatory

2) I almost never read mails, plus email notifications are inconsistent if you're not inside an ecosystem, e.g. Apple/Google. For me it is not a reliable way of communication

slwvx
Could be a good feature for AnkiWeb.net
jdthedisciple
I made the exact same thing except with notifications instead of email.

I called my app "Mnemonist".

My last as just hasn't gotten around to shipping it yet...

alwayslikethis
With the number of cards I have in Anki, something like this is going to fill up my inbox. Recent Anki versions ship a much more advanced algorithm called FSRS which performs much better (fewer reviews for the same recall). If you haven't tried it in some time, I recommend taking another look. Also, many note taking programs have ways to export to anki, which is probably more pleasant than adding notes directly.
tsekiguchi
Readwise also has this feature. I get a daily email with a random assortment of highlights that have been pulled in from multiple sources (Reader, Notion, Kindle, etc.)

The product benefit in their case is that it's kind of like Zapier, but for notes.

https://readwise.io/

andai
The comments here remind me of the HN comments when Dropbox launched!
andai
Cool idea! What were your other 3 projects this year?
dirkc
This looks like it might have been one of them? https://ginkgovest.com/.

*edit* seems different - google search led me astray. I didn't realize ginkgo is a tree with a distinctive leave

iskrataa
I kicked off the year with a web app that summarises foreign books using AI.

2nd is a desktop emulator of an iPod (macOS only)

3rd is a Stardew Valley tool

Let me know if you need a URL for any of them :D

kazinator
I can't find them who would use this over Anki or AnkiDroid.

I have hundreds of items to review. I wouldn't want that in my inbox.

iskrataa
I get you. In cases where you have that many cards, that's definitely not for you.

My case is rather 2-3 quotes from a book I just read of 5ish articles per week which I find interesting and don't want to forget (so it will email them again to me after some time so I can reread). Thanks for the feedback!

kazinator
Anki scales down to a few questions, and is a local-only app requiring no infrastructure for mail delivery.

A book you read will eventually turn to twenty books you read, and then you have 40 to 60 quotes and so it goes.

christin369
This is really impressive! Would you mind sharing some analytics like subscriber count or DAU? I'm curious to learn more about how your platform is performing. Thanks!"
iskrataa
Thank you! Sadly, it's just at the start of the project so I don't have anything to share yet.

I'll give an update after some time of collecting metrics. You can also follow me on X to be in touch with the project.

BenMorris-Rains
Cool idea, can it just be an app that sends me notifications instead of the email? Anything that goes to my email is basically a black box and I won't see it. I am an email hoarder and I don't clean them up... Once every other year or so I'll try.

The only thing that helped was routing "updates" and "promotions" straight to my trash, but I miss things sometimes that way.

Scea91
Seems like the root cause is not email.

I am curious how “another app” would be better in your situation than just setting up an email rule (3 min task at most) for this mailer if you truly care about it.

dirkc
Well done shipping your project! I like the low-friction demo on the page! I assume I'll receive an email in a few days from now? Are you using those emails for marketing/a mailing list?
iskrataa
Thank you! You're both right—you'll get your repetitions, and I'll add you to the user mailing list (unless you opt-out).