ColdNet

How it started

I was stuck at the bottom of a mountain with a twisted ankle, two hours from the nearest hospital, and no phone signal. I wanted to know if it was broken or just sprained. Normally I'd ask ChatGPT. But there was no internet, no Wi-Fi, nothing. Just me and a question I couldn't answer.

The thing is, an offline map app had just guided us up and down that same mountain in near-whiteout conditions. It worked perfectly without a connection. So why couldn't there be an offline AI that does the same thing for knowledge?

That thought wouldn't leave me alone.

Building it

I started with small open-source language models. Llama, Gemma, 3-billion parameter models that could run on a phone. They could answer questions, but they made things up constantly. ChatGPT runs on something like 1.2 trillion parameters. These tiny models couldn't come close on accuracy.

So I flipped the approach. Instead of making the AI think, I made it search. I compressed 50,000 Wikipedia articles into a 5GB local knowledge base, built a retrieval pipeline, and had the model find and present real answers rather than generate them from nothing. Hallucinations dropped to practically zero.

What it is

ColdNet is the most accurate offline knowledge app on iOS. Fully private, fully local. No internet, no cloud, no accounts. One purchase, no subscriptions. Your questions never leave your device.

• ●Works anywhere. No Wi-Fi, no signal, no problem.
• ●Private by design. Nothing leaves your phone.
• ●Built for Apple Silicon. Fast, efficient, local.
• ●Clean and minimal. Just you and the answers.