Problem: People can't send cryptocurrency payments without internet connection.
Real Scenarios:
- Rural areas with spotty cellular coverage
- Natural disasters when cell towers are down
- International travelers avoiding roaming charges
- Remote markets where vendors have no data plans
Send Stellar payments offline by bouncing them through nearby phones via Bluetooth/Wi‑Fi (AWDL) until someone with internet submits them to the blockchain.
- Sender (offline or online)
- Creates and signs a Stellar transaction locally (no internet required)
- Broadcasts the signed XDR to nearby phones using Apple's MultipeerConnectivity (Bluetooth/Wi‑Fi/AWDL)
- Mesh network
- Nearby peers discover each other and forward messages
- We deduplicate each payment by its XDR and add jittered debounce to prevent storms
- Relay (any online peer)
- First online device submits the exact signed XDR to Horizon (unchanged)
- On success, it broadcasts a payment confirmation back through the mesh
- For the demo, it also distributes rewards (see Rewards) using on‑chain classic payments
- Receiver and Sender update
- Receiver’s funds settle on Stellar as a normal on‑chain payment
- Offline devices request balance via mesh from any online peer and update their UI when the reply arrives
- MultipeerConnectivity (MCSession) for device‑to‑device transport
- NWPathMonitor to detect transport changes and restart discovery when needed
- Debounced discovery restart to avoid flapping
- Per‑transaction dedupe (by escrow XDR) + 3s + random jitter before relays
- Optional Offline Mode toggle to suppress internet probes for demos
balanceRequest(accountId)sent to peers when you tap Refresh while offline- Any online peer replies with
balanceUpdate(accountId, balance, sequence) - UI shows a small toast and a loading state until the response arrives (auto‑times out)
Fee split (1% of gross):
- 0.5% Broadcaster (first hop)
- 0.1% Relayer (online submitter)
- 0.4% Protocol
Current implementation:
- Rewards are sent from the relayer’s wallet immediately after relay:
- Broadcaster receives 0.5% (skipped if same as relayer)
- Protocol receives 0.4% at
GA6TY5O2JF2CDMY3LUFJEOV5IOQX5IALNQ5DRS4HU35VOPXNGDVZGG7R - Relayer keeps 0.1%
Smart contract:
- Contract:
CACKTHTCAZW5EK5YCVEVLBIEN536TTBLMUQIJKLOICBDVBKANECMVZZC(https://stellar.expert/explorer/testnet/contract/CACKTHTCAZW5EK5YCVEVLBIEN536TTBLMUQIJKLOICBDVBKANECMVZZC) - Native XLM SAC:
CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC - Method:
record_and_distribute_rewards(sender, recipient, broadcaster, relayer, gross_amount, token_address) - App scaffolding exists (
SorobanHelper) and can be switched on when Soroban RPC simulate/sign/send
- On‑chain double‑spend protection via Stellar sequence numbers
- Relay cannot modify payments: any change invalidates the sender’s signature
- Mesh replay mitigations: per‑XDR dedupe, TTL, debounce, and no infinite rebroadcast
- Future hardening: signed mesh payloads, short timebounds on offline txs, fee‑bump/sponsorship support
- Open
mesh=-pay.xcodeprojin Xcode 15+ - Run on two or more iPhones (grant Bluetooth/Local Network permissions)
- In the app:
- Create/fund wallets (testnet) and open Mesh Network screen
- Toggle Offline Mode for demo if needed
- Try sending from one phone while it’s offline; keep another phone online as relay
Permissions to allow on first run: Bluetooth, Local Network, Camera (for QR scan)
- Rewards:
RewardsContract.swiftcontractAddress(Soroban)nativeXLMAddress(SAC)protocolAddress(protocol recipient)
- Mesh debug:
MeshNetworkView.swift- Offline Mode toggle
- Restart Discovery button
- Path summary (Wi‑Fi/Cellular)
https://drive.google.com/file/d/1a6iFqncbkXofjnWoCiOD4tLn1dypIbBV/view?usp=sharing
If you would like to test the product send us your email so we can send you a test-flight link as it is a mobile app still in beta and not currently publicly available.
https://drive.google.com/file/d/1aE-XOFBTOnBlINOAudVSS0zLiArPbsbK/view?usp=sharing
