Terms

Last updated September 22, 2026

What Proseidon is

Proseidon is a writing app. It runs as a desktop app and as a web app at app.proseidon.io. The app is free. An account is optional. With one you can sync and back up your projects, share them with people you invite, and publish pieces for readers. We may add paid plans for heavier use later.

Your writing is yours

You own everything you write in Proseidon. When you sync, you give us permission to store your work and send it to your own devices and to the people you share it with. That's the only permission you give us. We don't use your writing to train AI.

Your account

• Keep your sign-in details to yourself. If you sign in with Google, the security of your Google account protects your Proseidon account too.
• Don't use Proseidon to store or share anything that's illegal where you live, and don't attack or overload the service.
• Work that only lives on one computer or in one browser is your responsibility. The app warns you when something isn't backed up.

Sharing and publishing

When you invite someone to a project, they can read it and, depending on the role you give them, edit it. When you publish a piece, anyone with the link can read it (and the password, if you set one). You're responsible for what you publish.

No guarantees

Proseidon is still being built. Keeping your work safe is our first priority, but the service comes as it is, without warranties. As far as the law allows, we're not liable for losses caused by using it. Keep your own copies. "Download my library" in the app makes that easy.

Stopping

You can stop using Proseidon whenever you like. Your local copies stay on your devices. To delete your account and synced data, email deep@proseidon.io. We may suspend an account that abuses the service, and we'll tell you why.

Changes

If these terms change in a way that matters, we'll update this page and email account holders. If you keep using the cloud features after that, you accept the new terms.