Splitrix — Decentralized Expense Splitting on Aptos

Splitrix is a Splitwise-like dApp built on the Aptos blockchain. Create groups, add shared expenses, and settle debts using AptosCoin, with a modern React + Vite frontend.

• Testnet contract address: 0xf50e2e1a30a1bfc7301cfb163b22c1ae77251ccd1b8e71ec81f08c32406dabfa

Screenshots

Dashboard -

Shows all the associated groups and their lifetime statistics

Balances -

Shows the current net balance of the user in the group

Add Expense -

Shows the form to add a new expense

Bills -

Shows all the bills in the group

Settle Bills -

Settle the bills individually or all at once

Members -

Shows all the members in the group

Contacts -

Shows all the contacts in the user's address book

Prerequisites

• Aptos CLI (for keys/accounts and network access)
• Node.js (v18+ recommended)
• pnpm (package manager)

Environment

Create a .env from .env.sample and fill the values. Required keys:

# Network used by SDK and wallet adapter
VITE_APP_NETWORK=testnet

# Publisher account (the address that compiles/publishes the Move package)
VITE_MODULE_PUBLISHER_ACCOUNT_ADDRESS=0x...
VITE_MODULE_PUBLISHER_ACCOUNT_PRIVATE_KEY=0x...

# Deployed module address (auto-written by publish script, or set manually)
VITE_MODULE_ADDRESS=0xf50e2e1a30a1bfc7301cfb163b22c1ae77251ccd1b8e71ec81f08c32406dabfa

The Move module name is splitrix. Frontend derives fully-qualified function names from VITE_MODULE_ADDRESS.

Install

pnpm install

Move contract

• Compile

pnpm move:compile

• Publish (deploy)

pnpm move:publish

This script uses VITE_APP_NETWORK, VITE_MODULE_PUBLISHER_ACCOUNT_ADDRESS, and VITE_MODULE_PUBLISHER_ACCOUNT_PRIVATE_KEY, and writes the resulting object/module address into VITE_MODULE_ADDRESS in your .env.

Frontend

• Run dev server

pnpm dev

• Build for production

pnpm build

What you can do

• Create groups and become the admin/member automatically
• Add expenses with flexible splitting:
  • Select exactly which members participate in the bill
  • Choose split mode: percentages or integer shares
  • Percent mode requires an exact total of 100.00% (10,000 basis points); the UI provides an equal-split helper that distributes any remainder (e.g., 33.34/33.33/33.33)
  • Shares mode converts shares to basis points, distributing any remainder to ensure an exact total of 10,000
  • The payer can be included; their share does not create a debt
• On-chain debt tracking with netting:
  • Debts are stored per (debtor → creditor → bill_id → amount)
  • Reverse-pair netting is applied when adding expenses (reduces cycles) and bill IDs are tracked FIFO per pair
• Settle debts in AptosCoin per bill or all-at-once per creditor:
  • Pay one bill at a time or “Settle All” for a creditor in a single transaction
  • Settlement updates per-bill amounts and maintains FIFO order
• View activity across all your groups (bills and member participation)
• Manage contacts on-chain:
  • Store address → name on-chain, with list and single-name view APIs
  • UI supports QR sharing/scanning and shows your own address as “Me” for clarity

Tech stack

• Move smart contract (Aptos)
• React + Vite + TypeScript, Tailwind CSS
• @aptos-labs/ts-sdk, Aptos Wallet Adapter (Petra)
• TanStack Query for data fetching/caching

Notes

• Ensure your Aptos CLI and the wallet are on the same network as VITE_APP_NETWORK.
• If you already have a deployed contract, set VITE_MODULE_ADDRESS directly and skip publish.
• Percent splits must sum to exactly 100.00% before submitting an expense; use “Split equally” to auto-balance.
• When “Settle All” is used for a creditor, all outstanding per-bill entries for that creditor are paid in one transaction.