Show HN: I made a privacy friendly and simple app to track my menstruation (play.google.com)

732 points by stormqueen ↗ HN
Hey HN, after the app I actually used to track my period wanted me to log in and save my data in the cloud, I decided to write my own.

Most apps in this area are based on a subscription model and display far too much information anyway.

For me, a simple calendar is enough where I can add a few notes if necessary.

So that is the result of my work - a simple design and the data is only saved on the smartphone.

230 comments

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That's awesome, thank you! So many of the existing women's health related apps are creepy like that (cloud).
Very good! These apps are really valuable in a world where many of these apps get really bloated
To help drive home the privacy angle, you might consider open-sourcing it and also making it available on F-Droid. Also, why does it say "in-app purchases"? If this is a simple calendar I don't see why any purchasable extras should be necessary.

(While many in the HN crowd lack the requisite equipment to make use of your project, we do have girlfriends, wives, sisters, and daughters who might benefit from a privacy-respecting app like this.)

What's the status of trustworthy reproducible build systems for deploying open source code to apps on Android?
well, zero. just like apple. since there's no convenient way for the user the validate anything they are installing other than "the app store said so"
This is a response to a question of Google Play’s reproducibility which is moot because of the distribution mechanism. *Android* in general does have reproducibility especially from third party repos like F-droid.
correct.

sadly fdroid usage is close to zero. and even there verification requires adb hacks and very expert users, even for basic hash checking.

The in-app purchases are a dealbreaker. Not only is there no reason for it, but it necessitates the integration of Google Play Services.

If the goal was to be privacy-centric, it already fails at that for this alone.

And if the goal was to profit off of women's need for privacy-centric period tracking, then there is absolutely no reason not to find a proper FOSS alternative that cares about its users more than making passive income for the developer.

An in-app purchase is an automatic dealbreaker? Doesn’t that depend on what it actually is?

It could be an in-app purchase for themes or something like that. It can be a “thanks for supporting the app” cosmetic badge, completely optional, just there to buy a coffee for the author. But you’re dealbreaking it before you even see it?

In-app purchase != data collection

Also, regarding FOSS alternatives, you should know that FOSS does not mean “free from payment.” It technically doesn’t even mean “free from data collection.” It just means that the source code is available under a free and open source license. FOSS isn’t necessarily “free as in beer” and the FSF explicitly defines it that way. It’s more important that you’re offered the freedoms of the open source license and ability to get the source code. Whether or not you pay is a separate issue entirely.

it is the moment google allows you to target who have spend on that app.

but yeah, you already have:

- system apps for play service which run all the time and can access all apps' storage.

- all apps can ask the OS for a list of other installed/recently open apps. whats app request that list every minute.

- etc. not going to list all the crap you can use to target individuals on apple and android. there's plenty.

my point is, in the end. apps with purchase option are the least worse from the official stores. chill.

Are you responding to the right comment? What you’re saying seems completely unrelated to what I was responding to RIMR about.

If your issue with this app being posted to HN is the mere existence of the app on the Play Store (including all of the store and the OS’ existing flaws), I don’t see how that’s supposed to be a constructive or useful discussion relevant to this app.

They are responding to the part of your comment that says

> An in-app purchase is an automatic dealbreaker? Doesn’t that depend on what it actually is?

Hardly unrelated

Don’t tell someone to chill just because they take an opposing viewpoint. It’s disingenuous and attempts to paint them as emotional and irrational.
> all apps can ask the OS for a list of other installed/recently open apps. whats app request that list every minute.

REALLY? That was blocked on iOS like a decade ago.

Damn, that's quite the lecture. Where did GP say that FOSS means free of payment? I only see criticism of the payment method (along with justification), not the need for payment. There are other ways of collecting payment than using Google Play Services. Plenty of apps that are open source are not free-as-in-beer (as you pointed out). OP could keep a Play Store version with in-app payments for users who don't care, but also release an F-Droid open source version that takes payments through Stripe or some other alternative. This would be approximately 10x better anyway due to "commission."
It's unfair to expect someone to work for free. In-app purchases are a common and reasonable way for programmers to sustain themselves while providing a valuable service to users. After all, programmers, like everyone else, need to make a living.
GP did not say they expecting someone to work for free. They took issue with the payment method and explained why.

If the app required payment by giving your name, address, credit card, and more to "Jimmy" (some person you don't know and don't trust) who will be contacting you to collect, and somebody said "I don't know Jimmy and I don't really trust this. I'd prefer to use a trusted method of payment" would you reply, "You just don't want people to make a living!" I would really hope not.

It turns out "I want privacy first and open source" is still a dog whistle for "I don't want to pay for anything".
If paying for something deanonymizes me, as a Google Play purchase would, then it isn't fulfilling the privacy part of the deal at all.

More importantly, if privacy centric apps raise the barrier for entry to include licensing fees, then most people are going to choose the "free" alternatives that get paid for by selling their metadata. If you actually care about protecting users' privacy, you should avoid gatekeeping the technology behind a paywall.

There are plenty of Free (as in beer + as in freedom) period trackers out there that I would be happy to donate time and money to help develop. The closed-source for-profit version that demands that I disclose my identity to Google before I get started is dead-in-the water, having failed to be suitable for any purpose than making the developer a bit of cash while pretending to care about women's privacy in a world that wants to imprison them for a miscarriage.

Indeed, given the legal complications of reproductive health in some states, privacy would be at the top of my mind if considering to use an app like this.
Not sure why you're being down voted, this is a great point. And a depressing one.
Not a woman, so take this with a grain of salt.

A few years ago, I wouldn't have been very bothered by the privacy implications of an application like this, but for obvious reasons it's become much more prudent to consider them. Were I a woman I'd be deeply troubled to use an application like this, no matter how good, without some kind of ironclad proof of a privacy respecting codebase. Imagine logging patterns indicative of a pregnancy followed by an abortion, and then imagine selling this data to Texan bounty hunters[0] or any other nefarious actor in your jurisdiction. The stakes have become too unacceptably high to use an application like this without knowing with perfect certainty that it is safe to use.

Which isn't to cast any aspersions on OP for developing it. But the game has suddenly become very dangerous, and despite their reassurances, this is in fact a weapon of potentially lethal consequence.

[0] https://www.villanovalawreview.com/post/2229

Exactly. A few years ago I would have thought that this kind of take was absurdly paranoid... but here we are.
OP seems to embrace Google Analytics, as stated on their own site.[1] So, you might be barking up the wrong "if you want true privacy, avoid Google" tree, here, sadly.

(I agree with you but OP probably thinks/feels differently about Google - itself.)

[1] - https://www.siekmoeller.com/ladylog/impressum.html

I use GA only for the homepage not the app itself
Fathom Analytics offers a straightforward, privacy-focused alternative to Google Analytics.

Unlike Google, which collects extensive data to build detailed user profiles (read the link for details), Fathom uses a variety of techniques such as hashing to anonymize data, ensuring it cannot be traced back to individuals.

Their approach complies with major privacy laws like GDPR and CCPA, removing the need for intrusive cookie consents.

Plus, with Fathom, you get essential analytics in a simple, user-friendly format, making it a smart choice for sole-developer sensitive health-related applications.

https://usefathom.com/why-fathom-analytics/privacy-focused-w...

Or check the plethora of great GA alternatives like:

Plausible

Piwik Pro

Simple Analytics

Wide Angle Analytics

Pirsch

Umami

etc.

https://european-alternatives.eu/category/web-analytics-serv...

For a solo dev that would rather spend time on other things, who prioritizes ease of use and minimal setup, Fathom might be the better choice.

If they value transparency in how tools work and possibly require some customization, Plausible’s open-source platform could be more suitable. Both offer strong privacy practices.

Each of the others you list also offer flavor variety: Piwik Pro for comprehensive, regulation-compliant analytics; Simple Analytics and Wide Angle Analytics for straightforward, cookie-free tracking; Pirsch for performance-sensitive server-side implementations; and Umami for developers who prefer open-source solutions with full control over their data.

Rather than going into depth on all that, we've found recommending Fathom is the simplest thing that can possibly work for someone just getting visitor and campaign info off their web home page, very fire and forget, read the weekly emails.

If that's ever not enough, the others do have their places.

(I am a maker of Wide Angle Analytics)

Wide Angle is cheaper and grows with your needs.

You can start simple, and then dive deeper. Additionally, we support consent-based tracking and optional Personal Data processing for those who require more in-depth data.

But nothing stops you collecting just clicks/views/sources/campaigns with no set-up beyond dropping in a small script. No cookie banner required by default.

And yes, I am biased. :)

I’m a plausible fan. Very simple and affordable. Privacy friendly
All these are great but I was lacking more advanced features from them.

So I created openpanel.dev which is a combo of Plausible and Mixpanel.

Privacy focused as well!

Check it out https://openpanel.dev

Is this an ad? It reads like an ad.
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It's a product with a high NPS, meaning, people who choose it for use cases are likely to "ad"-vocate for it for those use cases.
I wasn't aware they made their NPS public.
In-app purchases: You can buy another theme if you want. There is no need to do that - the whole functionality is available anyway. I thought it would be nice to at least have the opportunity to make some money from it...

I haven't thought about open-sourcing it... Maybe I'll think about it...

You can always pop it on GitHub with no license. You retain copyright, nobody can do anything with it. Would enable users to report bugs there in the Issues area, or you could make a basic GitHub Pages site, or there's a wiki or discussion forum.

If you did add a license, users could submit PRs of bug fixes or new features. If you don't have a lot of users it probably would get very little traffic and so not become burdensome. (And you can always ignore it... Not ideal, but life comes first)

If you care about privacy and want to have some fun with the license idea, you can add an Ethical Source license, so anyone who uses your code has to comply with a code of ethics. (https://ethicalsource.dev/licenses/) Maybe a license that says you cannot use this if you actively work against women's reproductive health/freedoms?

Nothing wrong with wanting to make some money. Especially with something like additional themes.

Please just don't hide existing/important features :).

Making additional themes be in-app purchases seems like a reasonable way of funding the project. You might want to specifically say in the app description in the store what the in-app purchases are. I was kind of suspicious until I saw this explanation.

"Free on F-Droid, $3 on the Play Store" is another approach I've seen (e.g., Conversations and DAV5x).

Good point - I changed the description!
Well done! It's great to see more female developers building apps for women. I agree with other commenters that you'd get a lot of mileage out of open sourcing it and doubling down on the privacy / local storage angle. It would help you get press coverage if you want to grow the user base.
> you'd get a lot of mileage out of open sourcing it

I’m not sure. Maintaining an open source project requires even more time than a closed source project. You can have a community-oriented closed source project, too.

> and doubling down on the privacy / local storage angle

Yeah!

There's a difference between open sourcing and "maintaining an open source project".

Realistically most open source android apps do not receive many, if any, contributions from outsiders. Being open source does however signal the app isn't likely to become a paid shitfest.

Hosting the source code outside of Github/Gitlab/etc is enough to make maintenance easier already.
Exactly. I wish people would get over this idea that the only two options are closed source or setup and maintain a vibrant community of contributors. It's perfectly fine to just put the code on github and never look at it again. If you're willing to take an additional 30 seconds to be honest in the README.md about your intentions, even better.

Code doesn't have to be perfect to be open.

Open sourcing would just be a PR tactic IMO. Since it's all local storage anyway, there shouldn't be many security maintenance issues. I just think it gives a nice story angle for bloggers and tech press. But agreed, trying to build an active open source project with a community around it is a whole other ballgame and likely not worth the trouble.
It's not just a PR tactic. If the app is closed source, how do you know it's all local storage? Because someone on the internet said so? These days you can't really MitM and investigate the network connections.
Agree with you if privacy first is the goal then open sourcing it is absolutely the right move. However, it IS still possible to MITM these days - although more difficult.

frida.re has a ton of useful features and community tooling built around it including scripts that will let you "un-pin" certificates by hooking and rewriting the functions that verify whether cert pinning worked or not.

https://frida.re/

https://codeshare.frida.re/@masbog/frida-android-unpinning-s...

Neat, thank you! I hadn't heard of frida.re. I'll definitely have to dig in to that!
This is cool, I always thought ovuview was a little too public, with its notifications. Are you planning on features that track likely ovulation time for fertility purposes?
I'm not planning on that at the moment. The next feature is a graphical representation of the period duration. But I added this on my list
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With most other apps they wouldn't even have to, police buy it from data brokers.
Congrats! Adding 2 cents here: my wife only used a menstruation tracker when we were trying to conceive. Having the app predict/notify the ovulation day was useful.
The opposite can also be true - at least for knowing the relative risk of getting her pregnant.
Sorry to hijack a bit here, but have any good links to open source baby tracking apps that allow sharing between partners? The popular options out there on the app stores are a privacy dumpster fire.
No experience but Alternativeto.net might help.

The sharing part makes that a little less common.

I used this for our newborn recently and was very impressed with how flawlessly the partner sharing worked - https://mangobaby.app It is not open source. But didn't look suspicious like the other apps on the store. The privacy labels on the iOS App Store seemed acceptable too (for us).
I’d recommend FindMy, but it only works for iBabies.
tell me about it. And I can never Green text bubbles from my droid baby.
If you're up for self-hosting, there's BabyBuddy[0]. There's no first-party native app, but it is a decent web app and there's some third-party apps/integrations. And of course, multiple users is a priority. No affiliation, just a user :)

[0]: https://github.com/babybuddy/babybuddy

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I think it's such a great name, simple and endearing. Thanks for sharing it I'll be sure to have a look.
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Why do you think using vi to write data to disk makes it any more private?
Well, it does have the advantage of being FOSS, extensively reviewed by many eyes, and known to not send any data off-device. It also has the advantage of already existing and being packaged for most platforms already. I've used vi(m) plus a little awk for ex. calorie counting because it's already there and I'm not a software developer. That's not to say that it's a good choice, necessarily, just that it does have advantages. Something about the best tool is the one you have....
It would be awesome to have a temperature tracker here as well.
The comments on this post are interesting:

1. Some insist that the source code be made public.

2. Some insist that there be no in-app purchases.

3. Some insist that there be no analytics whatsoever.

Each of the above has some legitimate reason. However, do privacy-focused apps need to play by different set of rules?

If so, what special monetization models would make sense to folks on here? #AskingForAFriend

Probably some sort of donation model that would result in a coffees worth of money for a 100 hours of work.
I don't know, I think shotgun-style generalized criticism that doesn't always apply (or 'applies' but comes from a place of 'everything-should-be-free-entitlement' which is toxic to indie creators) is pretty standard fare for Show HNs. Not good, to be sure! But to be expected haha :)
- Patreon if what you're doing lends itself to regular updates - PayPal or other payment processor if your project could use donations - Subscription based Server As A Service for things that need data syncing between multiple platforms (eg: the public/client parts can be Free Software, the server part just exposes an API, and you make it clear what data is transmitted to the server remaining solely on the user's device) - Consultancy to assist with installation/training if your product is complex
Menstruation consultant
I don’t have experience with the Android App Store, but normal subscriptions/IAP/initial purchase on iOS would protect the user info during purchases.

Apple tells you nothing about the user. You can choose to give them a UUID that they’ll echo back when you query their API about the subscription/transaction, but that’s up to you.

Apple will not give a name, email, Apple ID, phone number, location, or anything else.

See the data here: https://developer.apple.com/documentation/appstoreserverapi/...

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I think this will be the model case for future historians to study software market in our pathetic times.

Period tracker app is something a programming student can do. (Maybe with some questionable choices resulting in potential data loss, but this can be fixed.) You don't need a degree to make basic cycle prediction, and you can't reason about anything else without real medical knowledge. So this is something that can be done once in open source, and put onto F-Droid for everyone to use (and, of course, it already has such apps). Something as simple as calculator does not need “cloud account”, nor internet connection at all.

But how are we going to make money on that? How do we grab data that can be sold from users?

So the snake oil festival starts. From cute backgrounds to “AI advice”, lots of nonsense gets invented to grab and hold user attention, and hordes of paid biological word generators pretend that they have never felt “safe” before using “this app”. Many choose to directly ask for sex and pregnancy planning data to be sure they are the first who can sell it. Everything is done to smoke-screen the fact that users are only needed to input as much data into the machine as possible.

“Privacy focused” is just one of such fake labels. It means “we will try hard to protect any data we can sell from other bastards who want to do the same”.

Needless to say, little data brokers just follow the example of platform owners who run the circus, and dream to become data mafia kingpins one day. They benefit from each other, so you won't find simple apps with no strings attached being recommended by the app stores, because they are Bad for Business™.

As for third party “analytic solutions”, in simple terms, you simply let them collect some data on your users to get some charts and generally useless information (useful information costs money — sometimes a lot of money; each time Google or Apple decide whether they should do X or not, it costs Facebook a large sum, and new agreements behind closed doors).

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(Unfortunately, like most people here, I can’t actually speak to the experience using this app. Sorry.) That said I think you have a duplicated set of screenshots (maybe an old set?) that you might want to clean out.
For anyone on iOS, there is a cycle tracker built into the Apple Health app, so no third party app needed.

https://support.apple.com/en-us/HT210407

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This isn't targeted at OP. Sharing options doesnt mean that you shouldn't use the one this thread is about.
A valid point, I guess it rubs me wrong when the top reply is a negative comment about someone creating something themselves. It isn't nice or even necessarily valid.

Lots of founders could've been torn down at this early phase by crap like this.

My hypothesis: They need much more sun and water.

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This is par for the course. When you post about a product in a domain, people will discuss similar products. There's no targeted teardown.
The alternative proposed is for an entirely different platform than the OP app, so this seems like the perfect place for it.
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Great work and not to hijack – are there catalogs of “privacy focused” apps that don’t collect data or make remote requests? I would love a “ Kosher” badge like OU that tells me it’s a simple app (like yours) that provides utility without snooping
Using resources like F-Droid can help you find open source apps, which generally speaking, are very privacy friendly. I believe admittance into the default F-Droid repo doesn't allow trackers at all. Certain alternative front ends to the F-Droid repos, like Neo Store, can display privacy "scores" for individual apps.

There's also many groups that produce privacy-friendly apps, such as SECUSO[0] and Fossify[1]

[0]: https://github.com/SecUSo [1]: https://github.com/FossifyOrg

Shout out to secuso! Their apps might not be the prettiest but they absolutely work and they work well. Very useful
Great starting point thanks !
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When I was on Android I looked for a period-tracking app but could only find cloud-based ones, so I didn't track my period for many years. Appreciate you.
this app make me think of my lady, it might be useful for her
Are the use cases for period tracking: 1. helps planning (e.g. same way a weather app helps decision making around when to do / not do various activities), and 2. improves accuracy of estimating whether conception may have occurred (vs not tracking).

Are these correct; are there others?

If you’re regular and become irregular, it’s often a sign that something is off, or if you’re into middle age, that your body’s hormone balance is changing. In either case it’s something to pay attention to and maybe mention to your doc next time you see them.
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Use cases: health indicators, avoiding conception, achieving conception, and accurate pregnancy dating.

A well developed period tracking system with a long history is the Creighton Method. Briefly, individuals are trained person-to-person to collect consistent, reliable repeatable data. This can be compared between users, and has many uses. However, the data collection is inconvenient or in some cases impossible, and they will only train married women.

> and they will only train married women.

Who is 'they'? I'm going to have to dive into google aren't I?

Edit: Ok. Returned from rabbit hole. They = religious types who have thoughts about conception and contraception.

Just switched from Clue, thank you so much for creating this :) I love the simplicity and export feature
Thanks - that was my previous app too ;)
As a counterpoint to the sibling commenter, who seems intent on being negative: good job, I hope that the app is useful for plenty of folks!