Yapmesh moves signed, end-to-end encrypted messages, voice notes and files straight from phone to phone. Your key is your identity. A message rides in other people's pockets until it reaches the one it is for.
Free. Android 8.1 and up, 32-bit included. No phone number. iOS: in progress, not available.
When you need it most
Ordered by how many people it touches. Every number has a source at the end of the page. Each card names the rung of the ladder that does the work.
313
shutdowns in 52 countries in 2025; Pakistan alone had 206
When the network is switched off on purpose, phones are still on. Yapmesh links them over Bluetooth and Wi-Fi Direct, and a message keeps moving from pocket to pocket.
Bluetooth · Wi-Fi Direct110 M
people affected by disasters in 2025; after Hurricane Helene, 74% of cell sites were down across 21 counties78
Towers fail first. Yapmesh needs none. An SOS reaches every phone in reach and is carried on for a day; it relays before it is even read.
Bluetooth · pocket-ride · SOS1.7 M
pilgrims at Hajj 2026; 663 million visits counted at Maha Kumbh 2025; at Taylor Swift's Melbourne shows, data demand was about double what the carrier expected and fans could not post91011
A million phones on one cell is how a network collapses. Yapmesh grows stronger with every phone: files spread faster the more phones hold them, and a fenced group exists only inside the venue.
Wi-Fi Direct · fences3.1 bn
people live under mobile coverage but do not use the internet, mostly for cost12
Yapmesh began in a classroom with no Wi-Fi. A teacher's phone anchors a fence; the phones in the room share notes, voice and files with nothing to pay for.
Wi-Fi router · anchor fence$4.99 M
the global average cost of a data breach in 2026, a record high13
Some documents are not supposed to leave the building. A fenced group keeps a project's messages and files inside it: the files are encrypted before they are ever cut into pieces, so a phone that relays them holds a box it cannot open, and a phone that walks out loses the key.
Wi-Fi router · anchor fence300 M
people live outside any mobile broadband coverage; 2.2 bn are offline1214
A message waits in the outbox, then rides with whoever walks to town. Where the carrier delivers SMS, a stuck message can go by text, three pieces at a time.
pocket-ride · SMS100,000+
health facilities in sub-Saharan Africa without reliable power and internet, a programme estimate15
A ward group fenced to the ward: a member who walks out loses the key, and the group's files are encrypted before they are chunked.
Wi-Fi router · anchor fence7.4 / 10
is how seafarers rated their connectivity at the end of 2025, down from 7.816
A ship's Wi-Fi or a phone's hotspot is a rung of the ladder. No internet needed for the crew to talk, share manifests, or send a voice note down the shaft.
Wi-Fi router · Bluetooth64
shutdowns during protests in 19 countries in 20256
No phone number, no account, no server to subpoena. Presence only with consent, an alias that rotates every 15 minutes, history that can disappear, keys exchanged by a tap or a sound.
Bluetooth · sound · disappearing historyHow it works
A message goes on the best link it has, falls to the next after eight seconds, floods last. When every radio is exhausted it is marked stuck and offers the four hand-carried rungs. Tap a rung.
A phone that cannot see the recipient keeps a sealed copy and hands it over when they meet. The sender sees it happen.
1 · queued
Amina sends to Bilal. He is out of reach, so the message waits in her outbox, sealed.
2 · riding
Chen's phone, near Amina, takes custody. Amina's bubble says riding. Chen cannot read it.
3 · delivered
Chen meets Bilal. The message lands, the receipt rides back, Amina's ticks go double.
Verified with three phones on 8 Sep 2026: the middle phone held the message for a phone it had never met, 108 seconds later it landed.2
A file is cut into 16 KiB chunks under a Merkle root that is its name. Every phone that holds a piece serves it, rarest piece first, and each chunk is proven against the root before it is kept. A speedometer shows bytes per second and the time left.
Verified: 5 MB in 320 chunks, 0 rejected, identical hash on arrival; a 2 MB spreadsheet shrank on the wire and crossed in 4.6 s.193
SOS
When there is no signal to call anyone, the phones around you are the network. An SOS is the one message Yapmesh sends to everybody, and the one every phone passes on before it even reads it.
A press, a confirm sheet, an optional line of text and, only if you switch it on, your location and battery level. Nothing goes out by accident.
An SOS crosses up to 16 phones and lives for a day. Every phone relays it first and shows it second, then keeps it and hands it to every new phone it meets.
A full-screen red banner on every phone running Yapmesh in reach, even ones whose owners have hidden themselves. Hidden phones still acknowledge, so your "seen by" count is honest.
There is no server to throttle it and no account to suspend. Anyone with the app is a relay, and anyone can send one.
Verified on two phones on 7 Sep 2026: a long-press on one phone put a red "SOS from Bravo, next to you" banner on the other at once, with the sender's battery level.19
What it is not: a call to the police, an ambulance or a rescue service. An SOS reaches phones with Yapmesh within radio range or carried by people who walk, and it can fail silently when no phone is in reach. Use your country's emergency number whenever you can.
Features
Screens are from the current build on a Samsung Galaxy A07. Each feature says whether it has run on real phones.
Text, photos, quoted replies, reactions, stickers, places and contact cards, each sealed to the recipient with a key that ratchets forward every exchange.
Hold, speak, release. A four-second note is about 20 KB and arrived in three seconds over Bluetooth.
Anything in the room's drop zone reaches every phone in range, and each phone that has it helps the next.
Who is in is a signed record, not a server's opinion. Keys rotate when someone leaves; each sender has its own chain, so one message read later never unlocks the ones before it.
A circle on a map, a building's Wi-Fi, or the phones in a room. Walk out and the key leaves your phone; walk back in and, if the rules allow, it returns with the history.
Presence is a grant you give per contact: same network, same area, same room, same table. Everyone else sees a token that changes every 15 minutes.
Long-press to confirm. It goes 16 hops, lives 24 hours, is relayed before it is read, and carries your location only if you say so.
Voice and video over any IP link: a router, a hotspot, Wi-Fi Direct. Signalling rides the mesh; media is direct. No IP path, no call, and the screen says so.
A phone starts a hotspot and serves its own installer. The other phone scans two codes and installs, with no internet at all. The signer's fingerprint is on both screens.
Switch on the laptop rung and any browser on the phone's Wi-Fi or hotspot becomes a full node, files included.
When every radio fails the message says so and shows four buttons. Each does one thing on one tap. Nothing is sent without you.
A group message reads delivered to 3 of 5, read by 2, riding for 1. A phone that hides receives but does not count, which is the truth.
Per group: messages vanish after a chosen number of hours, and everything can be deleted when you leave. Enforced on every member's phone.
Fingerprint, face or pattern in front of Yapmesh, re-locking after a delay you choose. Yapmesh keeps no PIN of its own. It is a door on this phone, not a second layer of encryption.
Photos and videos can wait for a tap instead of appearing as they arrive, for when someone is looking over your shoulder. A half-arrived file never opens.
Spaces
The sentence has two readings, so here are both.
| Where you do it today | The Yapmesh space | What is different |
|---|---|---|
| WhatsApp group | Private group | Signed roster; keys rotate when someone leaves; no server holds the list. |
| Discord server | Open group | Anyone nearby can join; the key is public by design; no invite link to leak. |
| Telegram channel | Nearby room | Everyone in radio range reads it; each post shows how many phones saw it. |
| Instagram close friends | Presence grants | Only people you grant can sense you, and only to the tier you chose. |
| Snap Map | Mesh map | Phones and links coloured by rung; nobody's position leaves their phone. |
| Slack workspace | Anchor fence | A group that exists only around the office's phones; walk out and the key goes. |
| Facebook event | Geo fence | A circle on a map with a grace period; mock locations count as outside. |
| Google Classroom | Anchor-fenced group | The teacher's phone is the anchor; the room is the login. |
Groups and the Nearby room are verified on three phones. Fences are built, not yet field-tested.2
A sealed Yapmesh message is text. The share-sheet rung lets it travel through any app that carries text, and the receipt can come back the same way or over the radio later.
Tested end to end: SMS through Google Messages (three pieces, received intact on another phone), and text shared into Yapmesh from another app.4
Offered by the share sheet on the test phones but not yet tested end to end: WhatsApp, Gmail, Quick Share. Not yet tried: Telegram, Signal, Instagram DM, a printed QR. We list only what we tried.
Private by construction
Sealed frames only: a signed header and a ciphertext. Relays see a size and a hop count. A group's files are encrypted before they are cut into chunks, so a phone that holds every chunk holds a box it has no key for.
Nothing. There is no server, no account, no analytics, no crash reporter. This website has no tracker either. Nobody can be asked to hand over what nobody has.
A phone in the mesh, and, only if you allowed presence for that person, a token that changes every 15 minutes and means nothing without the secret you gave them. Hide, and even your name leaves the air.
Read the protocol specification Threat model and what is not protected
No independent audit yet. The code is open so that one can happen.
Compare
Every cell about another app comes from that app's own documentation, read on 8 Sep 2026. Where the maker does not say, the cell says so.
| Yap21 | Briar | Bridgefy | Berty | Meshtastic | FireChat (discontinued) | Signal | ||
|---|---|---|---|---|---|---|---|---|
| Needs internet | No | No; Bluetooth, Wi-Fi or memory cards; Tor when online22 | No for messaging, but internet is required the first time the app opens2324 | No; Bluetooth LE and mDNS25 | No; LoRa radio to radio26 | No27 | Yes28 | Yes29 |
| Needs a server | No | No; an optional Mailbox runs on your own spare phone2230 | A licence server on first run; the app logs in3124 | No; optional replication servers32 | No; optional MQTT gateway26 | Not stated; device to device27 | Yes33 | Yes; undelivered messages are held up to 30 days34 |
| Needs a phone number | No | No; a nickname and a password35 | Not stated on the app page; the privacy policy lists phone number among registration data2336 | No; no SIM needed2537 | Not stated; the docs describe no account system38 | Not stated27 | Yes; usernames are optional but a number is still required3940 | Yes41 |
| Offline range | Bluetooth, Wi-Fi Direct, Wi-Fi, SMS, screen, sound, any app | Bluetooth, Wi-Fi LAN, removable drives; no distance stated22 | Bluetooth LE, about 100 m by the maker's own estimate23 | Bluetooth LE, Android Nearby, Multipeer, mDNS; distance not stated32 | LoRa, kilometres; needs a separate radio from about $184243 | Bluetooth and Wi-Fi within 200 feet27 | None; no offline mode28 | None; no offline mode29 |
| Multi-hop relay | Yes, 8 hops; SOS 16; pocket-riding | No; syncs directly between contacts, forums replicate to subscribers22 | Yes; the app's hop limit is not stated; SDK profiles 50–2502331 | Not stated; "if a viable route exists"32 | Yes; default 3 hops, maximum 744 | Yes; limit not stated27 | No; server relayed33 | No; server relayed34 |
| Files offline | Yes, swarmed, any size | Images only, heavily compressed; file attachments are a stated missing feature4546 | Not stated for the app; the SDK lists files and images with no size2347 | Yes; media and voice memos, size not stated37 | No; text up to about 200 bytes3848 | Photos; size not stated27 | Online only; the limit is not on the support site49 | Online only; documents up to 2 GB50 |
| Groups offline | Yes, signed rosters, fences | Yes; private groups, forums, blogs35 | Public broadcast to everyone nearby; private groups not stated23 | Yes; multi-member groups32 | Yes; up to 8 channels51 | Yes; private groups up to 5027 | Online only; up to 1,00052 | Online only; up to 1,02453 |
| Open protocol | Yes, spec and core library open | Yes; GPL-3.054 | No; closed app and SDK behind a licence key; uses the Signal Protocol3155 | Yes; Apache-2.0 and MIT; the README says not yet for sensitive data25 | Yes; GPL-3.056 | No27 | Yes; AGPLv328 | No57 |
| Installs without a store | Yes, from a friend's phone | Yes; F-Droid and a direct APK58 | No; App Store and Play only23 | No for phones; Play and App Store only25 | Yes; F-Droid and a GitHub APK59 | Store apps only27 | Yes; a direct APK60 | Yes; a direct APK61 |
| Works on a laptop | Yes, browser on a phone's hotspot | Yes; Briar Desktop 0.6.5 beta, without Bluetooth62 | No47 | Partly; a command-line client25 | Yes; web and desktop clients, radio required63 | No27 | Yes; linked to the phone64 | Yes; linked, up to four devices65 |
| Free | Yes | Free; in maintenance mode since July 202646 | Free with ads and in-app purchases from $0.99 to $29.99; the SDK is sold per user2466 | Free; non-profit37 | Software free; the radio must be bought5643 | Was free; last update 2018, gone by 20206768 | Free; nonprofit, no ads69 | Free29 |
FireChat was last updated in 2018 and its service was gone by 2020.6768 Bridgefy: a 2020 Royal Holloway analysis found it offered no authenticity and no effective confidentiality; Bridgefy adopted the Signal Protocol in October 2020, and a 2022 USENIX Security paper broke it again.705571 Briar entered maintenance mode in July 2026.46 Berty's own README says it should not yet be used for sensitive data.25 Meshtastic needs a LoRa radio; the phone is only a client.38 Yapmesh has had no independent audit; read the security page before trusting it with anything.
Get Yapmesh
The first release-signed build is not published yet. The builds on our desk are signed with a development key and must not be installed from strangers. When the release exists, this box will show the file, its SHA-256 and the signing-key fingerprint, and the app's About screen will show the same fingerprint.
github.com/zakonweb/zynk/releases
Signing-key fingerprint
Compare it with About → Signer in the app and with the line on your friend's Share the app screen. If the lines differ, it is not the same app.
Android 8.1 or newer, 32-bit phones included. About 55 MB.
iOS: in progress, not available. No store listing exists yet, so there are no store badges.
Verified on 7 Sep 2026: a phone with nothing installed got Yapmesh from the phone next to it, 54.6 MB in about 45 seconds, and linked at once.17
On a phone with Yapmesh: Mesh → Use Yapmesh on a laptop. Join the phone's Wi-Fi or hotspot from the laptop and open the address shown. The browser becomes a full node: chat, files, the mesh map.
Open protocol
The wire format, the ladder, muling, the swarm, the ratchet, groups, epochs and fences are written down in one document with section numbers that the code cites. The protocol core is a pure Dart library with no app or brand code in it; it runs in the browser too.
Security researchers: the security page says how to report and what is in scope. Security and responsible disclosure
Origin
Yapmesh began with one teacher, a classroom full of Android phones, and no Wi-Fi. The first message crossed a desk over Bluetooth on 6 September 2026, and everything since is in the test log.
FAQ
Yapmesh keeps Bluetooth and Wi-Fi discovery running while it is open, under a visible foreground notification, and relays with a battery-aware policy. We have not yet measured a full day: every bench session ran on USB power. The number will be published when it is real.
One link is a Bluetooth or Wi-Fi Direct hop: a room, sometimes a building. A message can cross eight such hops, and it also rides in pockets, so the honest answer is: as far as people walk. On a shared Wi-Fi or hotspot, the whole network.
The message waits in your outbox and is offered to every phone that appears. After eight seconds with no way through it is marked stuck and shows four buttons: SMS, share, screen, sound. Nothing is ever sent without your tap.
Not the content: every direct message is sealed to one key with a Double Ratchet, every group message with its own message key. What a radio neighbour can see is that a phone is present and that frames of some size are moving. There is no server to compel and no phone number to look up. See the security page for what is not protected.
To receive a Yapmesh message that arrived as a text, so it lands in the chat instead of your inbox. Sending is never automatic: Yapmesh opens your own messaging app and you press Send. You can refuse the permission and Yapmesh still runs; the SMS rung then only sends.
A number is an account at a carrier, and an account is something that can be looked up, blocked, or handed over. Your identity in Yapmesh is a key made on your phone. You share it by QR, a tap, or a sound.
Your key is on that phone and nowhere else, so the identity is gone with it; contacts will see a new key when you come back and should verify it again. Turn on the app lock so a found phone shows nothing. Groups with retention forget old messages on every member's phone.
A contact code is a signed bundle you get in person: scan their QR, tap phones, or let the phones chirp to each other. All three are proximity channels; a forged code fails the signature and is dropped. Groups verify every roster record the same way.
Every number on this page, with where it came from and when it was read.