A blockchain-based invoicing solution designed to simplify cross-border payments for freelancers and clients worldwide.
🚀 Try it Live You can test the application directly on the Sepolia Testnet (Make sure to grab some Free MockUSDC from the faucet button!): 👉 Live Demo
This repository is divided into two main parts. Here is the current progress:
| Module | Status | Description |
|---|---|---|
| Backend | ✅ COMPLETED | Smart Contracts created, tested (100% coverage), and deployed to Sepolia Testnet. |
| Frontend | ✅ COMPLETED | Fully functional User Interface built with Next.js to interact with the Smart Contracts. |
The Decentralized Invoice System is a DApp (Decentralized Application) that allows users to generate invoice records directly on the blockchain and settle payments using Cryptocurrency (ERC-20 Tokens).
In the traditional world, international payments are often slow, expensive, and opaque.
- Freelancers often wait days for bank transfers to clear.
- Clients lose money on high currency exchange rates and administrative fees.
- Trust Issues: "Did you send the money?" vs "I haven't received it yet."
By moving invoices to the blockchain, we create a trustless system:
- Immutable Record: Once an invoice is created, it cannot be tampered with.
- Instant Settlement: Payments are made in stablecoins (like USDC), arriving in seconds, not days.
- Transparency: Both parties can verify the payment status in real-time on the blockchain.
If deployed to the Mainnet (Real World), this system is designed to help The Global Gig Economy.
Target Audience:
- Freelancers & Contractors: especially those working remotely for clients in different countries.
- International Clients/Businesses: who frequently pay vendors overseas.
Example Scenario: Imagine a Freelancer in Indonesia working for a Client in the United States. Instead of using a traditional bank (which involves IDR to USD conversion fees and 3-5 days waiting time), the Freelancer sends a Decentralized Invoice. The Client pays 500 USDC, and the Freelancer receives exactly 500 USDC in their wallet almost instantly. No middlemen, no hidden fees.
This project is organized as a monorepo. Click on the folder names below to explore the code:
/backend: Contains the Hardhat environment, Solidity Smart Contracts (InvoiceSystem.sol), Deployment Scripts, and Unit Tests./frontend: Contains the Next.js application, UI Components, and Web3 Integration logic.
- Language: Solidity & TypeScript
- Framework: Hardhat
- Testing: Mocha & Chai
- Network: Sepolia Testnet (Ethereum)
- Token Standard: ERC-20 (Using a custom Mock USDC for testing purposes)
- Framework: Next.js (React) & TypeScript
- Styling: Tailwind CSS & shadcn/ui
- Web3 Integration: Wagmi, Viem, & RainbowKit
- UX Features: Optimistic UI Updates, Skeleton Loading, Toast Notifications
Aether Blue (Jonathan Evan)
- Passionate Web3 & Blockchain Developer.
- Always learning and building in public.
I am building this project in public to learn and improve. I welcome any feedback regarding the Smart Contract logic, UI/UX flow, or security best practices.
Feel free to explore the code and open an issue if you find any bugs!