Simulating 2G to build an offline-first sync engine in Rust for rural clinics

hey dev.to,

so I am Mathéo, a 2nd year CS student at EPITECH Nancy (France). I want to share a project I have been building for the last few months: ZamSync.

Basically, it is a lightweight synchronization engine written in Rust. It is made for places where the internet is either extremely slow, drops every five minutes, or does not exist at all (think remote areas, Raspberry Pi nodes, offline-first apps).

The exact scenario I had in mind is the electronic Patient Information System (ePIS) of Bhutan. In rural Bhutan, district clinics need to register patients and sync the data back to central hospital hubs. The problem is the network: they often have 2G connections, 600ms latency, and constant cuts.

I looked at existing tools, but they either require a permanent stable connection or need a heavy database engine running on the client. I wanted to build something that:

1. Works over days of total disconnection.


2. Recover instantly if the network drops mid-sync (without duplicating data).


3. Runs on tiny hardware (under 10MB of RAM on a Raspberry Pi).


4. Keeps everything secure (encrypted at rest and in transit).

Here is the GitHub repository if you want to inspect the code:

Thanks for reading!

• Mathéo