One Shot Note —
A note that keeps itself private
Write it, get a link, share it in an email, chat or document. Encrypted in your browser — we never see it — it disappears on your terms.
Email is forever. Some things shouldn't be.
A password, a recovery phrase, a private address, a document that only one person needs to see once. Sent as a normal email, it lives on in the recipient's inbox, in backups, in every copy that was ever made — often unencrypted.
One Shot Note gives that content a lifespan you control. The sensitive part is never written into the email itself: it is encrypted in your browser, stored as an unreadable blob, and reached through a link that stops working the moment it is read or when the time you chose runs out.
Built into the compose window — no copy, no paste
One Shot Note is a widget inside the Onion Mail webmail. You never leave the email you are writing.
Open a new email
Start composing as usual. Next to the editor you find the One Shot Note button.
Write the note in the popup
Subject, message (plain text or Markdown), an optional password, and how long the note should live.
It is encrypted before it leaves your device
Your browser encrypts the note. We store only an unreadable blob — the key lives in the link, never on our server.
The link lands in your email
Click Create link and the popup closes with the link already inserted in the body of your message. Send it like any other email.
Everything a disappearing note should do
Designed to be safe by default and simple enough to use in the middle of writing an email.
Encrypted in your browser
The note is encrypted client-side before upload. The server receives an unreadable blob and never the key — a true zero-knowledge design.
Read once
Destroyed the moment it is first opened. Whoever opens the link second finds nothing — and you know the note was read.
Available for a period
Keep the note reachable for 1 hour, 24 hours, 3, 7 or 30 days. When the time is up, it is gone.
Optional password
Add a password — or let the widget generate a strong one — so that the link alone is not enough to open the note.
Encrypted file attachments
Upload a file up to 100 MB via Onion Drive. The link is added to your note and encrypted with it; the file auto-deletes after 24 h or first download.
Works anywhere
The link is inserted into your email, but you can paste it in a chat, a document or a ticket just the same. The recipient needs nothing but a browser.
Choose how the note disappears
Two modes, a safety net, and an optional password. Every setting is chosen in the popup before the link is created.
| Option | What it does | When to use it |
|---|---|---|
| Read once | The note is destroyed the moment it is first opened. A time limit is kept as a safety net in case it is never opened. | Passwords, recovery codes, one-time secrets. |
| Available for a period | The note can be opened as many times as needed until the chosen time elapses, then it is deleted. | Instructions or documents that a person may need to re-read for a few days. |
| Safety expiry | The maximum lifetime of the note, whichever mode you choose: 1 hour24 hours3 days7 days30 days | Always set — an unopened note never stays online forever. |
| Password | Optional. The recipient must type it to decrypt the note. Send it through a different channel than the link. | When the email itself could be forwarded or intercepted. |
| Format | Plain text or Markdown, so lists, headings and code blocks are rendered when the note is opened. | Longer notes, procedures, configuration snippets. |
Frequently asked questions
Where do I find One Shot Note?
In the Onion Mail webmail, open a new email: the One Shot Note button sits next to the editor. It is available to every account, free and premium.
Does the recipient need an Onion Mail account?
No. The recipient only needs a browser. They open the link (and type the password, if you set one) and the note is decrypted on their device.
Can Onion Mail read the notes?
No. Encryption happens in your browser, and the key is part of the link, which is never sent to our server. We store an unreadable blob and its expiry rule — nothing else.
What if the recipient never opens the note?
The safety expiry takes care of it: the note is deleted when the chosen time is up (from 1 hour to 30 days), even in Read once mode. Nothing stays online indefinitely.
How is this different from post-quantum messaging?
One Shot Note is about lifespan: a secret that disappears after being read. Post-quantum messaging via PQC Server is about long-term confidentiality against future quantum computers. They complement each other — and both live in your inbox.
Your next secret doesn't have to live in an inbox forever
Open a new email in Onion Mail and click One Shot Note. No setup, no separate account — encrypted, self-destructing, in one click.