A small, private, end-to-end encrypted messenger for 1:1 or group chats. Your keys never leave your device. The relay only ever sees ciphertext.
Unsigned build — Windows may show a SmartScreen prompt; choose "More info → Run anyway".
No accounts, no metadata harvesting, no giant framework — just a small tool built to keep a friend group's conversations private.
Messages are encrypted on your device with a Double-Ratchet protocol. Nobody in the middle — not even the relay — can read them.
Just a keypair generated on first launch. No email, no SMS, no profile to leak.
Not just 1:1 — create a group and invite everyone. Same Double-Ratchet encryption, no new crypto: each member keeps its own encrypted session with every other.
The relay stores and forwards opaque encrypted blobs. Your keys stay on your device, in your OS keychain.
Compare a safety number out-of-band to confirm who you're actually talking to. The app makes the difference clear.
If the protocol state ever looks wrong, the app pauses and tells you — it never quietly carries on.
A tiny, deterministic core. No giant framework, no telemetry, no ads.
A two-minute walkthrough of how BlatMSG keeps your conversations private — from key generation to verifying who you're really talking to.
On first launch, the app creates a keypair locally. No sign-up, no server-side account.
Send a friend a single-use link. Redeeming it establishes an encrypted session between your two devices.
Compare safety numbers out-of-band if it matters, then talk — every message is encrypted before it leaves your device.
Yes. Every message is end-to-end encrypted with a Double Ratchet (the same family of protocol pattern used by Signal). The relay only ever transports ciphertext, and your private keys never leave your device.
No. On first launch the app generates a keypair locally. There's no sign-up, no email, no phone number. You start a 1:1 chat or a group by sharing an invite link.
Yes. Create a group, invite everyone, and they land in one shared conversation. There's no new cryptography for groups — the app just keeps a normal encrypted 1:1 session with each member and fans each message out to all of them.
The app checks for new versions and updates itself automatically — you'll see an "Install & restart" prompt. Updates are cryptographically signed; the app only installs builds signed with the official key.
No. BlatMSG is a small private messenger for trusted friend groups — not a commercial product and not trying to compete with Signal. It uses proven protocol patterns rather than inventing new cryptography.
Coming soon. The core is cross-platform; native Mac and Linux builds are on the way.
No. BlatMSG is a closed-source personal project. It's built on well-known, proven protocol patterns (the Signal-style Double Ratchet via the open vodozemac library) rather than home-grown cryptography — but the app itself is proprietary.