UMBRA
Nothing stays. Nothing remains.

The first messenger that hides not just what you say, but that you talked at all.

No phone number. Message your friends. No one can even see that you did.

No phone number Free & private forever Nothing left on our servers Open-source you can verify
Anonymous
sealed · dissolving

01, Show me

Signal already hides what you say. UMBRA also hides who you talk to.

Here's the same handful of conversations arriving at two different servers. A normal messenger's server can read the pattern of your life, who, when, how often. UMBRA's relay only ever sees sealed, identical-size blocks under random codes it can't join up.

A normal server sees
The UMBRA relay sees
no link between the two sides.

Same conversations, one relay each. On the left, the server reads your life. On the right, the UMBRA relay holds sealed blocks it can't connect, so even we can't tell who you were talking to.

And it hides when you talk, too
See it · the wireemitting · constant
You , idle
outgoing rate1 pkt / 0.85s · unchanging
Your message rides out on the next pulse, bright, just for you.

Type all day or never open the app, the wire looks identical either way. So a watcher can't even tell when you're talking, never mind to whom.

Files hide their shape

Send a photo or a document, and the server carrying it can't tell how big it is, what kind of file it is, or who it's for. It's split into identical locked pieces under random names, and only the person you sent it to can put them back together.

Your address keeps moving

The private mailbox each friend uses to reach you quietly changes over time, and every friend gets a different one. Even a server that watched a single address for months can't build a lasting map of your life. The trail goes cold on its own.

Nothing to find if it's taken

Phone lost, or taken from you? Everything on it stays locked behind your passphrase. Someone who forces it open finds only noise, not your chats, not your contacts.

02, How it works

Three plain ideas. That's the whole trick.

01

No phone number

Your identity is just a key on your phone. Add a friend with a QR code or a one-time link, no number, no email, nothing that ties the app to the real you.

02

Sealed for one person

Every message is locked so only your friend's phone can open it, not us, not your network, not any server in between.

03

Vanishes on its own

Messages fade by themselves, on your screen and in transit. Keeping one is a choice you make, never the default.

lanternsealed · dissolving
message, fades when readsend
Add by code, no number
@lantern rotates · one-time link no phone · no email · just a key on your device.

This is the app, not a metaphor. Read a message and it dissolves. Add a contact with a code, never a number.

And it's a real, everyday messenger
Text & voice notes
Fast, sealed, and forgettable by default.
Photos & files
Sent in identical locked pieces, the server can't tell size or type.
Small groups
Sealed for each member; no server sees the group or who's in it.
Disappearing timers
Per-chat or per-message, on your terms.
QR & link invites
Add anyone in seconds, without a number.
iOS & Android
Native apps, from a single open-source core.
03, Everyday safety

A bodyguard on your phone, and one lock for everything.

Guardian, on your phone

Guardian quietly checks the links and files people send you for scams and phishing, and warns you in plain words. It runs entirely on your phone, so it can warn you, but it physically can't report you or phone home.

Message received:
Your account needs re-verification, tap secure-umbra-verify.link/login
!
Possible phishing, checked on your device
Lookalike domain imitating “umbra”. This is not an UMBRA address.
Illustrative. The scan runs offline with no network access whatsoever.

One vault for everything

UMBRA isn't only chats. Your files, passwords and notes live in the same sealed vault, protected by one key, the same encryption engine that guards your messages.

Lose your phone, or have it taken? It all stays shut behind your passphrase. Someone who forces it open finds only noise.

“Secure everything,” meant literally, not just what you say, but what you keep.

One key protects it all. A leak in one place can't unlock the rest.

04, Who it's for

For anyone the pattern could betray.

Journalists & sources

Protect the person, not just the story

A leak is often exposed by who met whom, not what was said. UMBRA hides the contact and the timing, no number links a source to a reporter.

Activists

Organize through a shutdown

Built for places where the network is watched. Constant cover traffic hides when you coordinate; reaching each other with the internet cut is on the roadmap.

Lawyers & doctors

Confidentiality that holds up

Privilege and patient trust depend on the record staying shut. No central store, no metadata trail, disappearing by default, less to ever be subpoenaed or breached.

Everyone else

Just don't want to be profiled

You don't need a threat model to want your relationships kept to yourself. Same protection, no configuration, private is simply the default.

05, UMBRA+

Privacy isn't the premium tier. It's the whole product.

Everything that keeps you private is free, forever. UMBRA+ adds room and comforts on top, and it's the one messenger where paying can't reveal who you are.

Free forever
UMBRA
Every privacy & security feature. No ads. No data sold.
  • Sealed messages that only your friend can open
  • No phone number, no email
  • Cover traffic & metadata protection
  • Network anonymity over Tor
  • Disappearing messages
  • On-device Guardian
  • Panic phrase & passphrase lock
// the free tier stays fully private, always.
UMBRA+ · premium
More room, same privacy
Everything in free, plus:
  • Bigger groups & more linked devices
  • Larger file transfers
  • Extra identities & separate vaults
  • Custom themes
  • Unlimited on-device transcription
€4.99
/ month
€39.99
/ year
€149
lifetime
Pay anonymously. Premium is settled through an anonymous token, the only messenger where paying can't reveal who you are. Pricing planned; the free tier never changes.
06, Don't trust us. Check us.

We'd rather be checkable than believed.

UMBRA's code is open-source, so anyone, a security researcher, or you, can read exactly what it does and check the promises on this page. Every release is signed, so you can confirm the app you're running really is the one we published. We won't call UMBRA “audited” until an independent firm has published one, that's planned. Full reproducible builds (rebuild from source, get identical bytes) are in progress.

And we tell you what we can't hide. On iPhone, to wake your phone for a new message, Apple's push system can see when your device receives something, never from whom, never what. That's a limit of the platform, and we say so rather than pretend it away. It's why we call UMBRA metadata-minimizing, never “invisible.” Full threat model, published at launch.

07, Under the hood

For the technically curious.

The rest of the page is the human version. Here's the engineering, condensed, for the people who want it, the cryptography, the verifiable builds, and where we're headed. Skipping it changes nothing about how the app feels.

Post-quantum, on every message

“Harvest now, decrypt later” is already a strategy, capture sealed traffic today, open it when a quantum computer arrives. UMBRA runs post-quantum crypto on every message by default, out of the box.

01
Post-quantum handshake. First contact mixes a classical key (X25519) with a post-quantum one (ML-KEM). To break it, an adversary has to break both, so today's captured traffic stays sealed against tomorrow's machine.
02
A post-quantum ratchet on every message. An SPQR-class continuous ratchet re-keys the session as you talk, so forward secrecy and post-compromise recovery survive a quantum adversary, not just the opening handshake.
03
Crypto-agility built in. Algorithms are named, versioned cipher suites with downgrade-protected negotiation. UMBRA can adopt tomorrow's cipher without a flag day and without breaking anyone mid-conversation.

Post-quantum on every message, the key exchange and the ongoing ratchet.

Verify the build, don't trust the vendor

EncroChat, Sky ECC and ANOM didn't fall to broken math. They fell because a server, an update channel, or a key could be reached. UMBRA's answer: hold nothing worth seizing at those points, and let you check the app you run really is the published source.

Open-source core. The full client and protocol are source-available, so researchers, and you, can read exactly what it does.
Signed build manifests. Each release is described by a canonical manifest signed with UMBRA's own post-quantum signature (ML-DSA / hybrid), so you can confirm the bytes you run match the ones we published, and reject anything signed by any other key.
Reproducible builds, in progress. The goal: rebuild from source and get the same bytes, so trust in us drops out entirely. Deterministic flags and the signing primitive exist today; the full pipeline is being wired up.
Verify this buildhonest status
Open-source core
Full client + protocol are source-available to read and rebuild.
Live
PQ-signed build manifest
Canonical release manifest signed with ML-DSA / hybrid; verifies against a published key only.
Built
Reproducible builds
Deterministic flags configured; full bit-for-bit pipeline not yet wired into CI.
In progress
Binary transparency log
Public append-only log of manifests so a withheld/targeted build is detectable.
In progress
External security audit
No third-party audit completed yet. We won't call UMBRA “audited” until a named firm publishes one.
Planned
Formal proofs
Machine-checked proofs of the core protocol are aspirational, not done.
Planned
One key hierarchy for the whole vault
One master key, many branches. A single key derives separate keys for conversations, media, attachments, backups, and your vault, so a leak in one place can't unlock the rest.
Every item, its own lock. Each note, file, or password gets a fresh key sealed under its branch, self-contained and tamper-evident. A wrong key fails closed.
Keys don't linger. Key material is wiped from memory the moment it's done, and never printed to a log.
Where we're headed, off the grid

A shutdown is now a routine tool of control. Because UMBRA seals and pads a message before it touches any transport, that sealed block doesn't care how it travels. These are roadmap directions, not shipping features.

313internet shutdowns recorded in 2025, a record. UMBRA is designed for the days the connection goes dark.
Roadmap

Works when the internet is cut

Nearby phones can relay for each other over Bluetooth and Wi-Fi mesh, messages hop device to device with no cell tower, no router, no ISP. A planned LoRa companion pushes that range across a town.

Still sealed. Still no phone number. The block is the same one that would have crossed the internet.

Vision

Over satellite, no SIM

Because a message is sealed and padded before transport, it can ride a satellite link still fully encrypted, the link only ever carries a fixed-size, opaque block.

No SIM, no carrier account, no phone number, a path to reach out from anywhere the sky is visible.

Off-grid mesh and satellite transport are roadmap directions, not shipping features. UMBRA today runs over the internet (optionally via Tor).

08, Honest status

What's built, and what's coming.

Overclaiming is the mistake that sank the last generation of “secure phones.” So here's the plain truth, updated as we ship.

Shipped

  • End-to-end encrypted core
  • Post-quantum by default
  • No-phone identity & pairing
  • Constant-rate cover traffic
  • Two-relay metadata split
  • On-device Guardian
  • Universal vault engine
  • PQ-signed build manifests

In progress

  • Reproducible-build pipeline
  • Binary-transparency log
  • Mobile beta (iOS & Android)
  • Embedded Tor by default

Planned

  • External security audit
  • Formal protocol proofs
  • Off-grid mesh & LoRa
  • Satellite transport
  • Group messaging at scale (MLS)
09, Questions

The honest FAQ.

Can I really talk to my friends without a phone number? +
Yes, none needed. Your identity is a key generated on your device. You add contacts with a QR code or a one-time link, so there's no number, no email, nothing that ties the app to the real you. Messaging works just like any other app, it's only the plumbing underneath that's different.
Is it actually open source? +
The core client and protocol are source-available, so security researchers, and you, can verify the claims on this page. We'd rather be checkable than take your word for it. Note: this is “open so it can be verified,” not “independently audited”, a third-party audit is planned, and we won't use the word “audited” until a named firm publishes one.
What does “our servers can't see who you talk to” mean? +
Most apps still see who you message, when, and how often, the map of your life, even when they can't read the words. UMBRA's servers only ever hold sealed, identical blocks under random codes, and the two sides of a chat never touch the same server, so there's no pattern for us or anyone else to draw. Constant cover traffic also hides when you're active at all.
What is the on-device Guardian? +
A local threat detector that scans links and file names you're sent for phishing and scams, and warns you in plain language. It runs entirely on your phone, it has no networking code at all, so it can't look anything up online or report what you were sent. It's advisory only: it never blocks, delays, or reorders your messages.
Is it really “post-quantum”? +
Yes, and by default on every message. The initial handshake mixes a classical key with a post-quantum one (ML-KEM), and a post-quantum continuous ratchet re-keys the session as you talk, so both the key exchange and the ongoing conversation resist a future quantum computer, not just the first message.
What if someone takes my phone? +
Everything on the device is encrypted at rest. You can lock the whole app behind a passphrase that's stretched with a memory-hard function and combined with a hardware-backed key, so a seized phone reveals nothing without your passphrase, even to someone who extracts the device key. A duress “panic” passphrase is part of the design for coercive situations.
Will there be a way to use it without the internet? +
That's on the roadmap, not shipping yet. Because UMBRA seals and pads a message before it touches any transport, the same sealed block can travel over a Bluetooth/Wi-Fi mesh between nearby phones, and, further out, over a satellite link, still end-to-end encrypted and still with no phone number. Today, UMBRA runs over the internet, optionally via Tor.
What about that iPhone notification thing? +
On iOS, Apple's push service can see the timing of an incoming message to wake your phone, not the sender, not the content. We disclose this openly rather than pretend it away. It's why we say “metadata-minimizing,” never “invisible.”
What will it cost? +
Core messaging and every privacy and security feature are free, forever. UMBRA+ is an optional premium tier (bigger groups, more devices, larger files, extra identities and vaults, custom themes, unlimited on-device transcription), planned at €4.99/month, €39.99/year, or €149 lifetime, settled through an anonymous token so paying can't reveal who you are. We don't run ads or sell data.
When can I use it? +
UMBRA is in active development, with a mobile beta in progress. Join the waitlist and you'll be among the first to get a build.
Be first

Leave one trace: your email.

UMBRA is in active development. For the first builds only, nothing else, no tracking.