Local-first by default

Libre Academy is local-first. By default:

Every course is a JSON file on disk (or in IndexedDB in the browser)
Progress, XP, and streak counters live in SQLite (desktop) / IndexedDB (browser)
The AI tutor runs against a local Ollama instance, so zero tokens get billed and there’s no cloud round-trip
Anonymous, cookieless product analytics (self-hosted, first-party Plausible) help us improve the apps. No personal data, no cross-site tracking, no error reporters, and you can turn it off anytime under Settings → Data & storage. Beyond that and the optional cloud-sync toggle, there are no outbound calls except the playground proxies

What does talk to a server?

A small, well-defined set of things:

The Anthropic backend for the AI tutor, if you flip it on under Settings (the local Ollama path stays default)
Cloud sync, if you sign in. Small JSON progress records, nothing else
The Rust + Go playgrounds at play.rust-lang.org and play.golang.org, since neither toolchain ships with Libre Academy
Product analytics (self-hosted, first-party Plausible). On by default, but anonymous and cookieless, with no personal data and no cross-site tracking. Turn it off anytime under Settings → Data & storage

Everything else, including PDF ingest, lesson rendering, and code execution for the in-browser languages, runs entirely on your machine.