Loan Application Example

Complete Loan Application Flow

This example demonstrates the complete loan application process from borrower perspective.

Overview

This example covers:

User registration and authentication
Submitting a loan application
AI credit scoring
Checking loan status
Accepting loan terms

Prerequisites

Backend API running at http://localhost:3001
Valid email address for registration

Step 1: Register a New Borrower

curl -X POST http://localhost:3001/api/auth/register \
  -H "Content-Type: application/json" \
  -d '{
    "email": "borrower@example.com",
    "password": "SecurePass123!",
    "username": "johnborrower",
    "firstName": "John",
    "lastName": "Doe",
    "role": "borrower",
    "phoneNumber": "+1234567890",
    "dateOfBirth": "1990-01-01"
  }'

Expected Response:

{
  "success": true,
  "data": {
    "user": {
      "id": "user_abc123",
      "email": "borrower@example.com",
      "username": "johnborrower",
      "role": "borrower"
    },
    "accessToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
    "refreshToken": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
  }
}

Save the access token for subsequent requests.

Step 2: Login (if already registered)

curl -X POST http://localhost:3001/api/auth/login \
  -H "Content-Type: application/json" \
  -d '{
    "email": "borrower@example.com",
    "password": "SecurePass123!"
  }'

Step 3: Submit Loan Application

export ACCESS_TOKEN="your_access_token_here"

curl -X POST http://localhost:3001/api/loans/apply \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "amount": 25000,
    "purpose": "business_expansion",
    "termMonths": 24,
    "monthlyIncome": 8000,
    "employmentStatus": "employed",
    "employmentDuration": 36,
    "creditScore": 720,
    "existingDebt": 15000,
    "collateralType": "property",
    "collateralValue": 100000,
    "businessRevenue": 120000,
    "businessType": "technology"
  }'

Expected Response:

{
  "success": true,
  "data": {
    "loanId": "loan_xyz789",
    "status": "pending_review",
    "aiRiskScore": 72.5,
    "riskLevel": "medium",
    "recommendedInterestRate": 8.5,
    "monthlyPayment": 1127.42,
    "totalRepayment": 27058.08,
    "estimatedApprovalTime": "2-4 hours",
    "breakdown": {
      "principal": 25000,
      "totalInterest": 2058.08,
      "effectiveAPR": 8.64
    },
    "aiAssessment": {
      "defaultProbability": 4.2,
      "riskFactors": [
        {
          "factor": "credit_score",
          "impact": "positive",
          "weight": 0.35
        },
        {
          "factor": "debt_to_income_ratio",
          "impact": "neutral",
          "weight": 0.2
        },
        {
          "factor": "collateral_coverage",
          "impact": "positive",
          "weight": 0.25
        }
      ],
      "recommendations": [
        "Good credit history",
        "Adequate collateral",
        "Stable employment"
      ]
    }
  },
  "message": "Loan application submitted successfully"
}

Save the loanId for tracking.

Step 4: Check Loan Status

export LOAN_ID="loan_xyz789"

curl -X GET "http://localhost:3001/api/loans/$LOAN_ID" \
  -H "Authorization: Bearer $ACCESS_TOKEN"

Response:

{
  "success": true,
  "data": {
    "loan": {
      "loanId": "loan_xyz789",
      "status": "pending_funding",
      "borrower": {
        "userId": "user_abc123",
        "username": "johnborrower",
        "creditScore": 720,
        "reputation": 0
      },
      "amount": 25000,
      "interestRate": 8.5,
      "termMonths": 24,
      "purpose": "business_expansion",
      "monthlyPayment": 1127.42,
      "createdAt": "2024-01-15T10:30:00Z",
      "approvedAt": "2024-01-15T12:15:00Z",
      "fundingDeadline": "2024-02-15T00:00:00Z"
    }
  }
}

Step 5: Get All User's Loans

curl -X GET "http://localhost:3001/api/loans/user/my-loans?role=borrower" \
  -H "Authorization: Bearer $ACCESS_TOKEN"

Response:

{
  "success": true,
  "data": {
    "loans": [
      {
        "loanId": "loan_xyz789",
        "amount": 25000,
        "status": "pending_funding",
        "interestRate": 8.5,
        "createdAt": "2024-01-15T10:30:00Z"
      }
    ],
    "summary": {
      "totalLoans": 1,
      "totalBorrowed": 25000,
      "activeLoans": 0,
      "completedLoans": 0
    }
  }
}

Step 6: Once Funded - View Loan Details

After a lender funds your loan:

curl -X GET "http://localhost:3001/api/loans/$LOAN_ID" \
  -H "Authorization: Bearer $ACCESS_TOKEN"

Response with Funding:

{
  "success": true,
  "data": {
    "loan": {
      "loanId": "loan_xyz789",
      "status": "active",
      "lender": {
        "userId": "user_lender456",
        "username": "janelender",
        "reputation": 4.8
      },
      "amount": 25000,
      "fundedDate": "2024-01-16T14:20:00Z",
      "disbursedDate": "2024-01-16T14:25:00Z",
      "maturityDate": "2026-01-16T00:00:00Z",
      "repaymentSchedule": [
        {
          "paymentNumber": 1,
          "dueDate": "2024-02-16T00:00:00Z",
          "amount": 1127.42,
          "principal": 956.09,
          "interest": 171.33,
          "status": "pending"
        },
        {
          "paymentNumber": 2,
          "dueDate": "2024-03-16T00:00:00Z",
          "amount": 1127.42,
          "principal": 962.86,
          "interest": 164.56,
          "status": "pending"
        }
      ]
    }
  }
}

Step 7: Make First Repayment

curl -X POST "http://localhost:3001/api/loans/$LOAN_ID/repay" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "amount": 1127.42,
    "paymentMethod": "bank_transfer"
  }'

Response:

{
  "success": true,
  "data": {
    "repayment": {
      "repaymentId": "repay_123",
      "loanId": "loan_xyz789",
      "amount": 1127.42,
      "principal": 956.09,
      "interest": 171.33,
      "paidDate": "2024-02-16T09:30:00Z",
      "transactionHash": "0x1234..."
    },
    "loanStatus": {
      "remainingBalance": 24043.91,
      "paymentsCompleted": 1,
      "paymentsRemaining": 23,
      "nextPaymentDue": "2024-03-16T00:00:00Z",
      "nextPaymentAmount": 1127.42
    }
  },
  "message": "Repayment successful"
}

Complete JavaScript Example

const axios = require("axios");

const API_URL = "http://localhost:3001/api";

class LoanApplication {
  constructor() {
    this.accessToken = null;
    this.loanId = null;
  }

  async register() {
    const response = await axios.post(`${API_URL}/auth/register`, {
      email: "borrower@example.com",
      password: "SecurePass123!",
      username: "johnborrower",
      firstName: "John",
      lastName: "Doe",
      role: "borrower",
    });

    this.accessToken = response.data.data.accessToken;
    console.log("Registered successfully");
    return response.data;
  }

  async applyForLoan() {
    const response = await axios.post(
      `${API_URL}/loans/apply`,
      {
        amount: 25000,
        purpose: "business_expansion",
        termMonths: 24,
        monthlyIncome: 8000,
        employmentStatus: "employed",
        creditScore: 720,
      },
      {
        headers: {
          Authorization: `Bearer ${this.accessToken}`,
        },
      },
    );

    this.loanId = response.data.data.loanId;
    console.log("Loan applied:", this.loanId);
    console.log("AI Risk Score:", response.data.data.aiRiskScore);
    console.log("Interest Rate:", response.data.data.recommendedInterestRate);
    return response.data;
  }

  async checkStatus() {
    const response = await axios.get(`${API_URL}/loans/${this.loanId}`, {
      headers: {
        Authorization: `Bearer ${this.accessToken}`,
      },
    });

    console.log("Loan Status:", response.data.data.loan.status);
    return response.data;
  }

  async makeRepayment(amount) {
    const response = await axios.post(
      `${API_URL}/loans/${this.loanId}/repay`,
      {
        amount: amount,
        paymentMethod: "bank_transfer",
      },
      {
        headers: {
          Authorization: `Bearer ${this.accessToken}`,
        },
      },
    );

    console.log("Repayment successful");
    console.log(
      "Remaining balance:",
      response.data.data.loanStatus.remainingBalance,
    );
    return response.data;
  }
}

// Usage
async function main() {
  const app = new LoanApplication();

  try {
    // 1. Register
    await app.register();

    // 2. Apply for loan
    await app.applyForLoan();

    // 3. Check status
    await app.checkStatus();

    // 4. Wait for funding (in real scenario)
    // await new Promise(resolve => setTimeout(resolve, 60000));

    // 5. Make repayment
    // await app.makeRepayment(1127.42);
  } catch (error) {
    console.error("Error:", error.response?.data || error.message);
  }
}

// Run
main();

Python Example

import requests

API_URL = "http://localhost:3001/api"

class LoanApplication:
    def __init__(self):
        self.access_token = None
        self.loan_id = None

    def register(self):
        response = requests.post(
            f"{API_URL}/auth/register",
            json={
                "email": "borrower@example.com",
                "password": "SecurePass123!",
                "username": "johnborrower",
                "firstName": "John",
                "lastName": "Doe",
                "role": "borrower"
            }
        )
        data = response.json()
        self.access_token = data["data"]["accessToken"]
        print("Registered successfully")
        return data

    def apply_for_loan(self):
        response = requests.post(
            f"{API_URL}/loans/apply",
            json={
                "amount": 25000,
                "purpose": "business_expansion",
                "termMonths": 24,
                "monthlyIncome": 8000,
                "employmentStatus": "employed",
                "creditScore": 720
            },
            headers={
                "Authorization": f"Bearer {self.access_token}"
            }
        )
        data = response.json()
        self.loan_id = data["data"]["loanId"]
        print(f"Loan applied: {self.loan_id}")
        print(f"AI Risk Score: {data['data']['aiRiskScore']}")
        return data

    def check_status(self):
        response = requests.get(
            f"{API_URL}/loans/{self.loan_id}",
            headers={
                "Authorization": f"Bearer {self.access_token}"
            }
        )
        data = response.json()
        print(f"Loan Status: {data['data']['loan']['status']}")
        return data

# Usage
if __name__ == "__main__":
    app = LoanApplication()
    app.register()
    app.apply_for_loan()
    app.check_status()

Next Steps

Lender Workflow: See Lender Example
Smart Contract Integration: See Smart Contract Example
API Reference: See API Documentation

Navigation Menu

Uh oh!

Loan Application Example

Overview

Prerequisites

Step 1: Register a New Borrower

Step 2: Login (if already registered)

Step 3: Submit Loan Application

Step 4: Check Loan Status

Step 5: Get All User's Loans

Step 6: Once Funded - View Loan Details

Step 7: Make First Repayment

Complete JavaScript Example

Python Example

Next Steps

Uh oh!

FilesExpand file tree

LOAN_APPLICATION_EXAMPLE.md

Latest commit

History

LOAN_APPLICATION_EXAMPLE.md

File metadata and controls

Loan Application Example

Overview

Prerequisites

Step 1: Register a New Borrower

Step 2: Login (if already registered)

Step 3: Submit Loan Application

Step 4: Check Loan Status

Step 5: Get All User's Loans

Step 6: Once Funded - View Loan Details

Step 7: Make First Repayment

Complete JavaScript Example

Python Example

Next Steps