Open-source Nostr messenger

Private messaging.No phone number required.

An end-to-end encrypted messenger for iOS, Android, macOS, Linux, and Windows.

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PsstPsst on macOS, light theme: chat list and conversation side by side

PsstPsst on macOS, dark theme: chat list and conversation side by side

Features

Core features.

DECENTRALIZED · END-TO-END ENCRYPTED

Nostr accounts and delivery

A randomly generated Nostr key pair is your account, so no phone number or email address is required. Encrypted messages are delivered through independent relays instead of one central messaging server.

End-to-end encryptedOnly the sender's and recipient's devices can read the message.

Sender's deviceEncrypts locally

Independent Nostr relaysNo central server

Relay ARelay BRelay C

Relays operate independently. No single relay controls delivery, and none can decrypt the message.

Recipient's deviceDecrypts locally

NEARBY

Message nearby without internet access

Use Nearby Messaging when speaking is difficult or inappropriate, or when the network is unavailable: on a plane, at a concert, in a crowded venue, or during an outage. PsstPsst discovers nearby devices over Bluetooth and exchanges encrypted text messages directly.

Bluetooth LEDiscovers nearby devices

Encrypted textExchanged directly

No internetDevice to device

CROSS-PLATFORM

Available on mobile and desktop

Use PsstPsst across phones, tablets, and computers. Desktop apps use a two-pane conversation layout designed for larger screens.

Security details

How data is protected.

Rotatable messaging keys

NIP-4E separates the messaging key from the account identity key. The messaging key can rotate without changing the account. Once old keys are removed, compromising the current key does not expose earlier messages.

Encrypted message envelopes

NIP-44 v2 encrypts the message contents. NIP-59 places the encrypted message inside a gift wrap that hides the sender from relays. The recipient opens the envelope on their device.

Keys never leave your device

Private keys and wallet connection secrets are kept in the secure storage provided by the operating system. Relays store and deliver only encrypted ciphertext, so they can never read your conversations.

Someday, maybe

Ideas we might explore.

A few things we are thinking about, in no particular order. Being listed here is not a promise to ship.

Small groups
Group conversations for a handful of people. Ten at most, maybe fewer.
Audio and video calls
Voice and video with the same end-to-end encryption as messages.
Built-in browser
Use Nostr apps without leaving PsstPsst.
Nearby over FIPS mesh
Rebuild Nearby Messaging on FIPS, a self-organizing encrypted mesh network built on Nostr identities. Nearby devices could reach each other over whatever transport is available, not just a direct Bluetooth link.
Silent Payments × NIP-17
When one PsstPsst user pays another with a silent payment (BIP-352), the sender's app notifies the recipient in an encrypted message, so there is no need to scan the blockchain.

Download

Choose your platform.

Get the latest release for your device.

Mobile

Phones and tablets

iOS

App StoreiPhone and iPadComing soon

Android

APKAndroid devices ZapstoreAndroid devices

F-DroidAndroid devicesComing soon

Desktop

Computers

Donate

Support development.

PsstPsst is free and open source. If it is useful to you, a donation helps keep development going.

Lightning

Zap sats instantly over the Lightning Network.

codytseng@getalby.com

Open Lightning wallet

On-chain Bitcoin

Send bitcoin on-chain to the following address.

bc1qwp2uqjd2dy32qfe39kehnlgx3hyey0h502fvht

Open Bitcoin wallet

GitHub Sponsors

No bitcoin? Sponsor the project on GitHub instead.

github.com/sponsors/CodyTseng

Become a sponsor

Larger donations

Planning something bigger? Get in touch first.

codytseng98@gmail.comSend an email