Klassified
Send a note or a file that encrypts in your browser, opens once, and leaves no readable copy behind - on our servers, in our logs, or in anyone's training data.
Free to use without an account. Optional free and paid accounts raise your sharing allowance. Klassified has its own home at klassified.app; until October 2026 it ran at classified.mainly.art, and links to that address still work.
Open Klassified ↗What it does
- Encrypts your note or file in the browser with AES-256-GCM before anything is uploaded.
- Puts the secret that unlocks the share in the link's URL fragment, which browsers never send to a server - so we hold only an unreadable blob.
- Self-destructs on first view or download, and expires at the time you choose, from 5 minutes to 24 hours.
- Optional password mode, where your password unlocks the share inside your browser instead.
The long version is in our how-it-works and FAQ, and the underlying ideas are explained from scratch in the guides library.
Platforms
- Web - klassified.app, any modern browser.
- Windows - from the Microsoft Store, with a global hotkey that turns selected text into a one-time link.
- macOS - a signed and notarized download from klassified.app.
Technical documentation
The app publishes its own engineering documentation, written against the shipped implementation rather than summarised from it:
- Security model ↗ Every cryptographic parameter in the v1 scheme, what the server can still observe, and the three limits the design does not solve.
- Request flow ↗ The two API calls behind a share, the enforced size and TTL limits, how expiry actually behaves, and the known failure modes.
- When to use it ↗ Worked handoffs, the constraints that decide the answer, and the four cases where a password manager or document service is the better tool.
Legal and support
Klassified's policies are published on its own site, where they apply:
- Privacy Policy ↗ What the service can and cannot see, accounts and Google sign-in, Stripe billing, diagnostics, cookies and advertising, retention, and your GDPR rights.
- Terms of Service ↗ Eligibility, accounts, moderation, plans and billing, the EU right of withdrawal, liability and Estonian law.
- Refund Policy ↗ The 14-day right of withdrawal, cancellation, plan changes and other refunds. Paid plans are sold by MAIN OÜ and paid through Stripe.
- Acceptable Use Policy ↗ What may not be shared, and how rules are enforced without reading encrypted content.
- Report abuse ↗ How to report illegal or harmful content shared through Klassified.
Questions about Klassified? The Klassified FAQ lists the support address, or use our contact page.