"Splitwise has 50M users and zero privacy. Split fixes that."
Every bill-splitting app — Splitwise, Venmo, PayPal — makes your amounts visible to everyone. On a public blockchain it's even worse: every expense is permanently on-chain for anyone to read.
You paid for the most expensive hotel room? Everyone knows. Splitting costs with a business partner? Your numbers are public forever.
Split fixes this. Expense amounts are processed inside a hardware-secured Intel TDX enclave via MagicBlock's Private Ephemeral Rollup. Nobody — not even the node operator — can read them. Only the final "who pays whom" settlement ever reaches Solana L1.
1. Alice creates a group → on Solana L1 (public: member list, group name)
2. Members add expenses via the TEE RPC endpoint:
Alice: Hotel $150 — split 3 ways ← shielded in TEE, never on-chain
Bob: Tapas $60 — split 2 ways ← shielded in TEE, never on-chain
Carol: Museum $30 — split 3 ways ← shielded in TEE, never on-chain
3. Alice triggers settlement → on-chain program computes:
a) Net balances per member
b) Minimum transfer graph (fewest transactions to settle all debts)
4. Only the transfer graph reaches Solana L1:
Bob → Alice $50 USDC
Carol → Alice $60 USDC
5. Each person clicks Pay Now → USDC transfer executes on L1
Individual expense amounts never appear on-chain. Ever.
| Primitive | How Split Uses It |
|---|---|
| Private Ephemeral Rollup (TEE) | Expense amounts submitted to tee.magicblock.app — shielded inside Intel TDX. Settlement math runs in the enclave. |
| Ephemeral Rollup | Real-time expense submission. Zero fee per expense. |
| Session Keys | Per-member auth to the PER. Only group members can read/write. |
| Commit Accounts | Settlement result committed from TEE back to Solana L1. |
| Data | Visibility |
|---|---|
| Group name & member list | 🌐 Public (Solana L1) |
| Expense descriptions | 🌐 Public (off-chain metadata) |
| Expense amounts | 🔒 Private — TEE only, never on-chain |
| Final settlement transfers | 🌐 Public (L1 after settlement) |
Even Split's own database never sees individual expense amounts. The privacy guarantee is hardware-enforced, not just a policy.
App: https://hackatonsplit.vercel.app
Deployed Program: FNm3MQiJMqdr1dBMtBLKHZ1Bn7AsjkoPd5g6eQo798Lz on Solana devnet
To test:
- Install Phantom wallet and switch to Devnet
- Get free devnet SOL at https://faucet.solana.com
- Go to https://hackatonsplit.vercel.app
- Connect wallet → Create Group → Add expenses → Settle Up
4 on-chain instructions deployed at FNm3MQiJMqdr1dBMtBLKHZ1Bn7AsjkoPd5g6eQo798Lz:
// 1. Create group on Solana L1
pub fn create_group(group_id, name, members) -> Result<()>
// 2. Submit expense — routed via MagicBlock TEE RPC
// Amount stays inside Intel TDX enclave
pub fn submit_expense(description, amount_lamports, paid_by, split_among) -> Result<()>
// 3. Settle — computes net balances + minimum transfer graph on-chain
pub fn settle_group() -> Result<()>
// 4. Execute a settlement transfer on L1 (USDC SPL token)
pub fn execute_transfer(transfer_index) -> Result<()>Full source: program/lib.rs
- Solana — base settlement layer
- MagicBlock Private Ephemeral Rollup — TEE privacy for expense amounts
- Anchor 0.30.1 — smart contract framework
- React + Vite + TypeScript — frontend
- @solana/wallet-adapter — Phantom/Solflare wallet integration
- Tailwind CSS + shadcn/ui — UI
- Vercel — deployment
# Frontend
git clone https://github.com/Yumstezy/hackatonsplit
cd hackatonsplit
npm install
npm run dev
# Smart contract (requires Anchor CLI + Solana CLI)
cd program
anchor build
anchor deploy --provider.cluster devnetThe gap nobody filled: every existing Solana privacy project is DeFi — dark pools, private swaps. Nobody applied TEE-backed privacy to the everyday human problem of splitting bills with friends.
The insight: privacy here isn't a technical feature — it's about human awkwardness around money. Split makes on-chain privacy feel natural and useful to non-crypto users.
The market: Splitwise has 50 million users. A privacy-first, stablecoin-native version with zero gas per expense and hardware-enforced privacy is a real product.
Built solo for MagicBlock Solana Blitz V2 · March 2026
Split — because your bills shouldn't be everyone's business.