Skip to content
meta matt gennings edited this page Jul 1, 2026 · 2 revisions

FAQ

Can you (the operator) read my note?

No. Your note is encrypted in your browser before it's sent, and the decryption key stays in the URL fragment, which browsers never transmit to a server. We store ciphertext we have no way to decrypt. This is a property of how the system is built, not a policy we promise to follow. The one honest caveat is below.

Then what's the catch?

The unavoidable one: because the same servers that store your note also deliver the JavaScript that encrypts it, a compromised server could in principle serve modified code that captures your note. This is true of every browser-based encryption tool, and no website can cryptographically prove to you that the code it served was honest. We state this plainly on the security page rather than pretend it away.

What happens if someone forwards my link?

Whoever holds the full link can read the note — once. The key is in the link. Send it over a channel you trust, to the person you mean. If that worries you, turn on passphrase mode: then the reader needs both the link and a passphrase you share separately.

Why does it ask me to click "Reveal" instead of just showing the note?

Because messaging apps (iMessage, Slack, WhatsApp, Signal) fetch links to build preview cards. If opening the link automatically fetched the note, that preview bot would be the first reader and would burn the note before you ever saw it. The click ensures a human — you — triggers the one-time read.

What if two people open the link at the same time?

Exactly one of them gets the note; the other sees "already read." The burn is a single atomic database operation with no race window. See How the burn works.

How long does a note last?

Until it's read, or until its timer runs out — whichever comes first. You choose 1 hour, 1 day, or 7 days when you create it. An unread note is deleted when the timer expires; a read note is deleted the instant it's read.

Is it really free?

Yes. It runs on AWS serverless infrastructure that costs effectively nothing at personal volume — it sits inside the free tier.

Can I run my own copy?

Yes, the whole thing is open source and deploys with one command. See Deployment.

Why "Cinder"?

A cinder is what's left after something burns — which is the whole idea. (The repo is still named blip, an earlier working name.)