What a private ebook library should mean, and how to check one

A library says a great deal about the person who keeps it: what they study, what they worry about, what they read at three in the morning. Handing one to a service is a matter of trust, and "private" is a word anyone can print on a page.

Here are the questions that tell you whether a library service means it. They work for any service, ours included.

Eight questions to ask

1. Who can see my books, notes and questions? The answer should be "only you, and whoever you choose to share with", not "our staff, for quality purposes".
2. Are my files changed? A library has no business rewriting your books, stamping them, or swapping them for its own copies.
3. Are my books used to train AI models? Ask for a plain no, written in the terms, not a setting you have to find.
4. When an AI is involved, what exactly does it receive, and where? "Your question" and "your entire library" are very different answers. So are "on our servers" and "a provider on another continent".
5. Is my reading tracked? Analytics, advertising trackers and third-party scripts all watch what you do. A reading app has no need for any of them.
6. Where is it stored, and under which law? Jurisdiction decides who can demand your data and what rights you have over it.
7. Can I take everything out, and delete it? Books, notes, highlights, positions, all of it, in a form you can use elsewhere, and a deletion that actually deletes.
8. Can I check? Open source code, or the option to run it yourself, turns a promise into something you can verify.

How Lexarii answers them

1. Private by default. Nobody sees your books, notes or questions unless you lend a book to someone, and you can take it back.
2. Never altered. Your files are stored exactly as you uploaded them. Everything Lexarii works out about a book is kept beside it, never written into it.
3. Never used for training. Your books are used only to serve you, and never used to train AI models.
4. The AI sees only what it needs. To answer a question, the model receives your question, the passages from your books most relevant to it, up to three of your own notes that bear on it, and the conversation so far; to describe a new book, a sample of its text. Never your name or your email address. Searching your books by meaning happens on our own servers. The model is reached through OpenRouter, in the United States, and we ask providers not to store or train on your data. That is a request we make, not a guarantee we can give, and the privacy notice says how providers are chosen.
5. No ads, no analytics, no tracking. One cookie, to keep you signed in. The site makes no requests to anyone else.
6. Stored in the EU, on servers we rent from Hetzner. Only the AI step leaves the EU, as above.
7. Yours to take, and to erase. "Download everything" gives you one file with your books, notes, highlights, reading positions, collections and conversations, while you subscribe and for 30 days after. Delete your account and your books and everything made from them are erased at once.
8. Yours to check. Lexarii is free software under the AGPL. The source code is public, and you can run it yourself with your own model, in which case nothing leaves your machine at all.

The honest trade

A hosted library asks for some trust: your files are on our servers rather than yours, and the AI step goes to a provider abroad. For many people that is a fair trade for not running a server. For some it is the wrong one, and for them the same software runs at home, free. We would rather you chose with the facts in front of you.

Try it

The demo needs no account at all. The privacy notice and terms are written to be read.