Messaging with real privacy

End-to-end encrypted conversations that are simple, fast, and designed to keep your data yours. No ads, no tracking, no compromise.

9:41
Alice
Hey, are you around?
2:30 PM
Yeah, what's up?
Just set up Lumero
2:31 PM
Nice!
It's way faster than I expected
2:31 PM
Everything is encrypted too
Not even the server can read it
2:33 PM
Love that. Privacy by default.
2:33 PM
Message...

Everything you need, nothing you don't

A full-featured messenger with consistent end-to-end encryption.

End-to-End Encrypted

Every message is encrypted before it leaves your device. Only you and your recipient can read it.

Group Chats

Coordinate with friends, family, or teams with the same strong encryption as direct messages.

Media & Files

Send photos, videos, and documents. All attachments are encrypted end-to-end.

Disappearing Messages

Set a timer for messages to automatically delete after they've been read.

Minimal Data Collection

No contact uploads, no message storage on our servers, minimal metadata by design.

Cross-Platform

Available on iOS and Android. Message anyone, from any device.

Trusted encryption under the hood

Lumero uses the Signal Protocol — the same proven standard trusted by security researchers worldwide.

1

Key Exchange

Start a conversation instantly, even if the recipient is offline. Keys are established automatically.

2

Unique Keys Per Message

Every message gets its own encryption key through a continuously rotating ratchet.

3

Forward Secrecy

Past messages can't be decrypted retroactively, even if keys are later compromised.

4

Self-Healing

The protocol automatically recovers and re-secures itself after any disruption.

// Signal Protocol session
struct Session {
  root_key: [u8; 32],
  chain_key: [u8; 32],
  msg_number: u32,
}
 
// Every message rotates the key
fn ratchet(session) {
  let (new_root, new_chain)
    = kdf(session.root_key,
      dh(our_key, their_key));
  let msg_key = kdf(new_chain);
  // old keys are deleted
  zeroize(session.root_key);
}

Privacy is a right, not a feature

We believe everyone deserves a space for honest, private conversation.

We can't read your messages

Your conversations never exist in a form we can access. No backdoor, no master key, no exceptions.

No ads, no tracking

No advertising, no data mining, no profiling. Lumero exists to serve you, not to monetize your attention.

Verifiable security

Compare safety numbers with your contacts to verify your conversations are truly private.

Get Lumero

Free and available on iOS and Android.