How we built Watsi Coverage without stable electricity, WiFi, or email
In this technical retrospective (2018), @necrodome shares practical architectural lessons learned from running, scaling, or migrating production software under lean constraints.
Core Principles for Independent Builders:
Defaulting to simpler architectures (such as monolithic frameworks, SQLite, or managed VPS) prevents early engineering bankruptcy.
Evaluating true compute and egress costs reveals that high cloud bills can often be slashed by 80%+ through judicious re-platforming.
Code you write at 2 AM as a solo engineer must be easy to debug six months later without complex microservice dependencies.
Community Debate Themes:
HN engineers debated the tradeoffs between cloud convenience and raw server economics, database indexing strategies, and resisting premature architectural complexity.
CATEGORY Frugal Engineering →
HISTORICAL ERA Cloud & Mobile Era (2014–2019)
COMMUNITY SCORE ★ 135 points
TOTAL DISCUSSIONS 25 comments
Wow, we came across the same thing while building epimetrics.in back in 2014-2015. We built the analytics engine and tested it in one mega Indian festival called "Kumbh Mela" with over 20 Million people gathering at one place. In our case, we had to struggle with the sheer amount of people as well.
We learnt a bunch of stuff and right away decided to have offline storage option and send data back to db when connection resumes. We also did the research on how to save battery life and use muscular memory to enable our users to use our system in that setup as efficiently as possible.
But at the end, it was very satisfying when we were leading on the front to spot the diseases. We helped attend over 2 million patients efficiently. If interested, I would love to share our insights plus few decisions which were very helpful for our adoption from health workers as well as govt health department officials.
Good work guys! Keep plugging! :)
Edit: Added festival name.
Nice.
Would have been more helpful if specifics were mentioned. E.g what Remittance service was used to pay with your US bank account? What network of telco? What did you use to build your app. PWA?
That way people that are well versed with Uganda can give feedback.
I never thought of the idea of using PIN terminology rather than password. I'll have that in mind.
I'm quite surprised that 100GB is $450. Uganda is known to have better rates. MTN is less than half of that [1]
[1] http://ugbusiness.com/1183/looking-for-the-best-internet-plan-in-uganda-heres-some-data-for-you
If anybody from Watsi sees this, we've spent years working on and perfecting offline-first distributed data sync, we've released it as MIT/ZLIB/Apache2.
We've had navy warships running the system on ancient hardware, and lots of people in the Open Source community have run it on low power devices, like raspberry pi and dirt cheap android phones.
Would love to chat, my email is in my profile.
I wish all app designers would consider designing apps that function offline. It's infuriating to visit a web page that has been read before only to find that the browser won't show it because the network is unreachable.
Great read! The bit about the time stuck out at me. With Internet access comes `ntp`, but without it... just how well tuned is the timekeeping circuit in cellphone chipsets, and how much did that even matter?