In 2016 purchased and jailbroke 20 iPhone 4, and later upgraded to 30 iPhone 5s on iOS 9.3
I wrote a custom theos tweak which injected an HTTP server into Snapchat.
A raspberry pi was running an nginx server as a load balancer across the 30 iPhones.
I developed an Android app called "Casper", which was a 3rd party Snapchat client. It sent http requests to my load balancer server to fetch signed security tokens from a random iPhone, which spoofed that it was the official Snapchat app.
The Snapchat APIs believed my app was the real app, so it could download and view snaps without the sender knowing it was even opened.
Self hosted an iPhone farm :)
Here's a link to my tweet with photos and videos of the setup for anyone interested!
https://twitter.com/LiamCottle/status/1406616490783117322