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Show HN: HCB Mobile – financial app built by 17 y/o, processing $6M/month (hackclub.com)

176 points by mohamad08 ↗ HN
Hey everyone! I just built a mobile app using Expo (React Native) for a platform that moves $6M/month. It’s a neobank used by 6,500+ nonprofit organizations across the world.

One of my biggest challenges, while juggling being a full-time student, was getting permission from Apple/Google to use advanced native features such as Tap to Pay (for in-person donations) and Push Provisioning (for adding your card to your digital wallet). It was months of back-and-forth emails, test case recordings, and also compliance checks.

Even after securing Apple/Google’s permission, any minor fix required publishing a new build, which was time-consuming. After dealing with this for a while, I adopted the idea of “over the air updates” using Expo’s EAS update service. This allowed me to remotely trigger updates without needing a new app build.

The 250 hours I spent building this app were an INSANE learning experience, but it was also a whole lot of fun. Give the app a try, and I’d love any feedback you have on it!

btw, back in March, we open-sourced this nonprofit neobank on GitHub. https://news.ycombinator.com/item?id=43519802

23 comments

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riffic
I really wish something like Hack Club existed while growing up, how empowering! great work.
miroljub
Why does it matter how old is the author?

We should judge software by the quality, not by authors age.

skylurk
I am surprised you managed to get those entitlements at all!

Did it help to be a non-profit?

sailfast
The OP built the React Native mobile app - not the entire platform / company. Some folks commenting like they built the company. Just a point of clarification.

Great work! Keep building OP!

mandeepj
It’s the same BS that people have at LinkedIn - leading a $250B initiative or increased revenue by $100B

OpenAI’s executive claiming - made one of the top visited websites :-)

rahimnathwani
This is great!

I'm curious whether you were able to build the app using backend APIs that were already built, or whether building this app created new requirements for those APIs?

LoganDark
> I adopted the idea of “over the air updates” using Expo’s EAS update service.

Be careful with this. If Apple finds out for instance, your app will still be taken down.

daredoes
Was just looking at this the other day for personal reasons. Great work!
mrb
That's awesome, and impressive you were able to build that. As an angel investor, my first question would be: how do you deal with financial fraud? Like users exploiting your app for money laundering via donations then spending... Any system that lets money get in and out is eventually used as a channel by launderers.
KenSF
HCB is an amazing Rails 8 app. It is the Rails app that is processing $6M/month.

https://github.com/hackclub/hcb

Excellent work on the mobile app though I would wonder, since HCB runs on Hotwire, why it was not written as a Hotwire Native app which would leverage the existing Rails Hotwire app and not require a complete rewrite?

cirrus3
What is this page of transactions for? https://hcb.hackclub.com/hq/transactions

I get that you want to be "open", but is everyone involved in these transactions ok with them being shared? Even if they are, this doesn't seem like a good idea security wise. I see partial account numbers and other IDs/numbers that I assume you'd prefer not be public, regardless of how insensitive they may seem now.

EXPENSIFY, INC. VALIDATION XXXXXX5987 THE HACK FOUNDATION +$0.89

FRONTING $10,000 TO CHRIS WALKER FOR GITHUB GRANTS MADE FROM PERSONAL ACCOUNT -$10,000.00

CHECK TO LACHLAN CAMPBELL +$800.00

Transfer to Emma's Earnings -$1,923.08

brahbrahbat
This is very helpful to the community. Great work.
throwaway5465
In accounting, finance, M stands for 'mille' aka 'thousand'. So the headline reads $6000/month.

Given how famed HN is for its pedantry I thought you may find this useful as sooner or later someone in your industry might make a judgement on it.

MM is million, BTW.

efilife
america is not the entire world

also a simple google search disproves what you are saying. M is correct

VoidWhisperer
No offense to the OP (what you did is great - as someone who had to pick up expo/RN on the fly for my newest job, it can be a bit annoying, and that is before all of the compliance nightmares associated with push provisioning) but the title does seem a bit disingenuous - it is phrased to make it sound like the app he built specifically is processing $6M/Month, where it is actually the platform that the app was built for that is
nxor
It doesn't "seem," it "is."
necovek
For something in the financial space, I don't see much (or really, any) tests in the code repository. CI also only has ESlint and prettier running.

How are you ensuring the application will remain maintainable in the future, you are not breaking existing stuff and integration with the actual platform is always up-to-date?

In short, what's the testing strategy for something that claims to deal with $6M a month?

If there is none, you likely want to read up a bit on things like Testing Pyramid, automated test strategies (unit-, integration- and end-to-end testing).

whynotmaybe
Thanks, you just made me realise that I can have OTA update for my app and could deliver more frequently without the play/store hassle!