How does this work?

Start a Chat

Share the invite code below with your peer, then paste their response.

---

Join a Chat

Paste the invite code from your peer.

Session Ended

All messages have been destroyed.

No trace of this conversation remains on your device.

New Session

Messages live in memory only

When you chat on Ephemeral, messages are stored only in your browser's RAM — never written to disk, never sent to a server, never stored in the cloud. When the session ends, the JavaScript array holding your messages is cleared. They are simply gone.

Direct peer-to-peer connection

Your messages travel directly between browsers via a WebRTC data channel. No relay server ever sees your data. The only server involvement is a public STUN server used during connection setup to discover your network address — it never sees message content.

End-to-end encryption

Every message is encrypted with XSalsa20-Poly1305 (via libsodium's crypto_secretbox). The encryption key is derived by combining two X25519 Diffie-Hellman exchanges:

• Identity keys (long-term) — authenticate both peers
• Ephemeral keys (per-session) — provide forward secrecy

The two shared secrets are combined via BLAKE2b to produce the session key. Fresh random nonces are generated for every single message.

Forward secrecy

Each session generates a fresh ephemeral key pair that is never stored. Even if your long-term identity key is compromised in the future, past session keys cannot be recovered.

Fingerprint verification

Both users' identity fingerprints are displayed at the top of the chat. You should verify these out-of-band (e.g., read them aloud on a phone call) to confirm you're talking to who you think you are.

What Ephemeral does NOT protect against

• Screenshots — your chat partner can screenshot the conversation
• RAM forensics — a device seized while the chat is active could theoretically have messages recovered from memory
• Compromised devices — malware or browser extensions on either device could capture messages before encryption or after decryption
• Unverified fingerprints — without out-of-band verification, a man-in-the-middle attack during the initial handshake is theoretically possible
• Network metadata — while message content is encrypted, the STUN server and network observers can see that two IP addresses are communicating

Identity storage

The only thing Ephemeral persists to disk is your long-term identity key pair, stored in IndexedDB. This lets you keep the same identity across sessions. No messages, contacts, or session data are ever written to any persistent storage.