A second brain that never leaves your browser. Drop notes in. Watch them connect. Ask questions across everything you've ever written.
Everything you see below runs entirely in your browser. No account. No server. No data collected.
Every note becomes a node. Shared ideas form edges. The longer you use Lumen, the more connected your knowledge becomes — visibly.
Notes live in your browser's storage. No server, no sync, no tracking. Your second brain stays yours — truly yours.
Open the tab and start writing. Export anytime. Works offline after first load. Free forever.
Pre-loaded with 12 notes on how to learn effectively. Click any node. Add your own. Everything stays in your browser.
This demo is the seed. Here's the shape of the full product.
Tag-based auto-linking, force-directed layout, zoom/pan, click-to-open, and a polished notes viewer. Add your own notes — they persist in your browser.
Real sentence embeddings (MiniLM-L6-v2) run in your browser. Toggle to "Semantic" in the graph to see meaning-based connections — no data leaves your machine.
Retrieval-augmented Q&A. Embeddings find relevant passages, the context is shown to you before sending, and the answer cites source notes. Bring your own free OpenRouter key.
Drop a PDF or paste a URL. Lumen extracts the text in your browser (PDFs never leave your machine), embeds the new content, and weaves it into your graph instantly.
Optional sync via a Dropbox or iCloud folder you choose. Your notes stay yours — Lumen still stores nothing on our side.