Group expense splitter with instant on-chain settle. Track shared expenses in a group, see who owes whom, and settle any balance in cUSD or USDC via MiniPay in one tap.

Built for Celo, ships as a MiniApp for Opera's MiniPay wallet.

• Create a group for roommates, a trip, a dinner, a household, anyone with a Celo wallet.
• Add an expense with amount, description, and who owes what share. Recorded on-chain.
• See running balances for the group: who's up, who's down.
• Settle any balance instantly by tapping "Settle", pushes a cUSD/USDC transfer through the connected wallet (MiniPay-optimized) and clears the debt on-chain.

No intermediary. Balances live in a smart contract on Celo. Settlement is a real wallet-to-wallet stablecoin transfer.

Live on Celo mainnet.

• Contract: 0x2979d1808024bd81eaba87942d79f7b2168e39c4, verified source on Celoscan.
• Frontend: splitpay-orpin.vercel.app, auto-deploys on push to main.
• Also deployed on Celo Sepolia at the same address (same deployer, same nonce, so CREATE produced the same address on both chains).

• Chain: Celo mainnet (chainId 42220). Sepolia (11142220) for testing.
• Contract: Solidity 0.8.28, Hardhat + viem test toolbox. Deploy via hardhat run scripts/deploy.ts --network celo.
• Frontend: Next.js 14 App Router, wagmi v2, RainbowKit, viem.
• Wallet: MiniPay auto-connect when running inside the wallet's in-app browser; RainbowKit's injected connector otherwise.
• Monorepo: Turborepo + pnpm workspaces.

splitpay/
├── apps/
│   ├── contracts/    Hardhat project (SplitPay.sol + tests + deploy)
│   └── web/          Next.js MiniApp frontend
├── package.json      Root workspace
└── turbo.json        Turborepo pipeline

pnpm install
pnpm dev            # starts Next.js dev server on :3000
pnpm contracts:test # runs Hardhat tests

Testnet:

pnpm contracts:deploy:celo-sepolia

Mainnet:

pnpm contracts:deploy:celo

Built as an entry for Celo Proof of Ship, Celo's monthly builder program. Group expense splitting is a real daily use-case that fits MiniPay perfectly (peer-to-peer stablecoin transfers between people who already know each other).