Privacy

Privacy Policy

Last updated: 27 July 2026

Callosium is built local-first. The short version: your notes never leave your computer, and we collect only the small amount of information we need to run your account, the waitlist, and this website. This page explains exactly what that is.

The part that matters most: your notes stay yours. Callosium runs on your own device, and your notes, files, and everything in your brain are stored as plain files on your machine. We never receive, store, see, or process your notes, on the free plan or any paid plan. There is no cloud copy of your knowledge on our servers. Even future sync moves your files through your own cloud (your Google Drive, OneDrive, Dropbox, or GitHub), not ours.

What we collect

Only what we need to give you an account and keep you informed:

Account information. If you sign in (with Google, GitHub, or email), we receive your name, email address, and profile picture, so we can create and identify your account.
Waitlist information. If you join the early-access waitlist, we store your email address, plus which plan you were interested in and which part of the page you signed up from.
Email, for updates. We use your email to send a welcome message and occasional product news. You can unsubscribe any time from a link in every email.
Website analytics. Like most sites, we use analytics to see which pages are visited and how the site performs. This uses cookies and collects standard information such as pages viewed, approximate location, and browser or device type. If you join the waitlist, we also share your email address with our analytics provider, so we can tell which channel your signup came from. We never share your notes.
Update checks. The Callosium app periodically asks GitHub whether a newer version exists. This is a simple version check and sends us none of your files or personal information. If you press Update in the app, it may also fetch the new version from npm.
Language model download, once. The first time you use meaning-based search, the app downloads a small open-source language model (about 130 MB) from Hugging Face, delivered through Amazon CloudFront. It is a plain file download: none of your notes, questions, or personal information are sent. After it is on your machine, search runs entirely offline, and keyword search works even before it finishes.

What we do not collect

Your notes, documents, or anything inside your Callosium brain.
The contents of your vault or files.
What you ask your AI, or what your AI reads or writes in your notes.

These never reach us. The app works offline for everyday use precisely because none of this needs a server.

How we use it

To create and manage your account and sign you in.
To run the waitlist and let you know when early access opens.
To send transactional email (a welcome message) and, if you opt in, product updates.
To understand and improve the website and product.
To answer your questions and support requests.

We do not sell your personal information, and we do not use your data for advertising.

Who we share it with

We use a small number of trusted providers to run Callosium. They process data on our behalf and only for the purposes above:

Supabase: authentication and database (your account and waitlist details).
Resend: sends our email.
Google: "Sign in with Google," and website analytics.
GitHub: "Sign in with GitHub," and hosting the app's update information.
Vercel: hosts this website.
Hugging Face (delivered via Amazon CloudFront): hosts the open-source language model the app downloads once, on first use of meaning-based search.
npm: distributes the Callosium package itself, including when you press Update in the app.

We share only what each provider needs to do its job, and nothing with anyone else except where required by law.

Cookies

This website uses cookies for analytics (to measure site usage) and, when you are signed in, to keep you logged in. You can control cookies through your browser settings.

How long we keep it

We keep your account and email information for as long as your account or waitlist entry is active, or as needed to provide the service. If you ask us to delete your data, we will, except where the law requires us to keep it.

Your rights

You can ask us to show you the personal information we hold, correct it, delete it, or stop sending you marketing email (or just click "unsubscribe" in any message). Email support@callosium.com to make any of these requests. And because your notes live on your own device, deleting them is entirely in your hands.

One thing you should know about deleting a note. Callosium keeps a local version history so you can undo a change an AI made to your notes. It lives in a hidden folder on your own machine (~/.callosium/history on macOS and Linux, %USERPROFILE%\.callosium\history on Windows), and it covers every folder in your brain, including any you treat as private. Deleting a note from your vault does not remove it from that history — that is the point of a safety net, but it means "deleted" is not the same as "erased". To erase a note permanently, delete it from your vault and delete that history folder. It never leaves your machine and we never receive it; it is yours to remove.

Security

We use reputable providers and standard protections to keep the limited information we hold safe. No system is perfectly secure, but the strongest protection here is structural: the most sensitive thing, your actual knowledge, never leaves your machine, so it is never ours to lose.

Children

Callosium is not directed to children under 16, and we do not knowingly collect information from them.

International users

Callosium is available worldwide, and the providers above may process data in different countries. By using Callosium you understand your information may be processed in those locations.

Changes to this policy

If we change this policy we will update the date at the top and, for significant changes, let you know by email or on this site.

Contact

Questions about your privacy or this policy? Email support@callosium.com.