💡 What is a Peer-to-Peer Lending DApp?
It’s a decentralized application that enables:
Borrowers to request loans
Lenders to fund those loan requests
Smart contracts to hold funds, enforce repayment terms, and release repayments
🧱 Tech Stack Overview
Component Technology
Smart Contracts Solidity
Blockchain Ethereum / Polygon (testnet)
Frontend React.js
Web3 Ethers.js or Web3.js
Storage (optional) IPFS for loan agreements/files
Wallet MetaMask
Dev Tools Hardhat or Truffle
🧠 Key Features
📌 For Borrowers:
Submit a loan request (amount, duration, interest)
View funding status
Repay loan
📌 For Lenders:
View available loan requests
Fund all or part of a loan
Receive repayment + interest
🔐 Smart Contract: Basic Example (Solidity)
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;
contract P2PLending {
struct Loan {
address borrower;
address lender;
uint amount;
uint interest;
uint dueDate;
bool funded;
bool repaid;
}
Loan[] public loans;
event LoanRequested(uint loanId, address borrower, uint amount);
event LoanFunded(uint loanId, address lender);
event LoanRepaid(uint loanId);
function requestLoan(uint _amount, uint _interest, uint _durationDays) external {
loans.push(Loan({
borrower: msg.sender,
lender: address(0),
amount: _amount,
interest: _interest,
dueDate: block.timestamp + (_durationDays * 1 days),
funded: false,
repaid: false
}));
emit LoanRequested(loans.length - 1, msg.sender, _amount);
}
function fundLoan(uint _loanId) external payable {
Loan storage loan = loans[_loanId];
require(!loan.funded, "Already funded");
require(msg.value == loan.amount, "Incorrect amount");
loan.lender = msg.sender;
loan.funded = true;
payable(loan.borrower).transfer(loan.amount);
emit LoanFunded(_loanId, msg.sender);
}
function repayLoan(uint _loanId) external payable {
Loan storage loan = loans[_loanId];
require(msg.sender == loan.borrower, "Only borrower can repay");
require(loan.funded && !loan.repaid, "Invalid loan status");
uint totalRepayment = loan.amount + (loan.amount * loan.interest / 100);
require(msg.value >= totalRepayment, "Insufficient repayment");
loan.repaid = true;
payable(loan.lender).transfer(msg.value);
emit LoanRepaid(_loanId);
}
function getLoansCount() public view returns (uint) {
return loans.length;
}
function getLoan(uint _loanId) public view returns (Loan memory) {
return loans[_loanId];
}
}
🖥️ Frontend Functionality (React + Ethers.js)
✅ Connect Wallet
const provider = new ethers.providers.Web3Provider(window.ethereum);
const signer = provider.getSigner();
✅ Submit a Loan Request
await contract.requestLoan(ethers.utils.parseEther("1"), 10, 30); // 1 ETH, 10% interest, 30 days
✅ Fund a Loan
await contract.fundLoan(0, { value: ethers.utils.parseEther("1") });
✅ Repay a Loan
await contract.repayLoan(0, { value: ethers.utils.parseEther("1.1") }); // amount + interest
🧪 Sample Hardhat Test
it("Should allow a loan to be requested, funded, and repaid", async () => {
const [borrower, lender] = await ethers.getSigners();
const Lending = await ethers.getContractFactory("P2PLending");
const lending = await Lending.deploy();
await lending.connect(borrower).requestLoan(ethers.utils.parseEther("1"), 10, 30);
await lending.connect(lender).fundLoan(0, { value: ethers.utils.parseEther("1") });
await lending.connect(borrower).repayLoan(0, { value: ethers.utils.parseEther("1.1") });
const loan = await lending.getLoan(0);
expect(loan.repaid).to.equal(true);
});
📁 Project Folder Structure
p2p-lending-dapp/
│
├── contracts/
│ └── P2PLending.sol
│
├── frontend/
│ ├── src/
│ │ └── App.js
│ │ └── components/
│ │ └── LoanList.js
│
├── test/
│ └── p2p-test.js
│
├── scripts/
│ └── deploy.js
│
├── hardhat.config.js
└── README.md
🌐 Optional Enhancements
NFT receipts for funded loans
Credit scoring (based on repayment history)
Partial funding from multiple lenders
Loan expiration logic
Frontend dashboard with filters and statuses
🚀 Deployment Steps
Deploy contract to a testnet (Polygon Mumbai, Sepolia)
Host frontend with Netlify, Vercel, or GitHub Pages
Integrate MetaMask for wallet connection
Include contract address and ABI for interaction
✅ Demo Flow Summary
Borrower connects wallet and submits a loan request
Lender browses open loans and funds one
Funds go to the borrower via smart contract
Borrower repays loan before due date
Smart contract sends repayment + interest to the lender
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