M-Pesa Express Integration Backend

This repository contains the backend implementation for integrating M-Pesa Express payments using Node.js and Express. The backend handles the initiation of M-Pesa STK push requests, enabling seamless payment processing in your application.

Features

M-Pesa STK Push Integration: Easily initiate M-Pesa STK push requests for payments.
Secure Token Management: Fetch and manage M-Pesa access tokens securely.
Environment Configuration: Use environment variables for sensitive data like API keys and secrets.

Requirements

Node.js v20.15.0 or higher
npm v10.7.0 or higher

Installation

Clone the repository:

git clone https://github.com/your-username/mpesa-express-backend.git
cd mpesa-express-backend

Install dependencies:
```
npm install
```

Create a .env file in the root directory and add the following environment variables:

BASE_URL=https://sandbox.safaricom.co.ke
CONSUMER_KEY=your_consumer_key
CONSUMER_SECRET=your_consumer_secret
SHORT_CODE=your_short_code
PASSKEY=your_passkey
CALLBACK_URL=https://your-callback-url.com/callback
PORT=3000

Start the server:
```
npm start
```

Usage

Use Postman or any HTTP client to send a POST request to http://localhost:3000/api/pay with the following JSON body:

{
    "phone": "2547XXXXXXXX",
    "amount": 100
}

Example Response

A successful response from the M-Pesa API might look like this:

{
    "MerchantRequestID": "12345-67890",
    "CheckoutRequestID": "ws_CO_123456789",
    "ResponseCode": "0",
    "ResponseDescription": "Success. Request accepted for processing",
    "CustomerMessage": "Success. Request accepted for processing"
}

Project Structure

mpesa-express-backend/
├── node_modules/
├── .env
├── package.json
├── server.js
└── daraja.js

server.js

import express from 'express';
import { initiateMpesaPayment } from './daraja.js';
import dotenv from 'dotenv';
dotenv.config();

const app = express();
app.use(express.json());

app.post('/api/pay', async (req, res) => {
    const { phone, amount } = req.body;

    try {
        const response = await initiateMpesaPayment(phone, amount);
        res.json(response);
    } catch (error) {
        res.status(500).json({ error: error.message });
    }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
});

daraja.js

import axios from 'axios';
import dotenv from 'dotenv';
dotenv.config();

const baseURL = process.env.BASE_URL;
const consumerKey = process.env.CONSUMER_KEY;
const consumerSecret = process.env.CONSUMER_SECRET;

// Function to get access token
const getAccessToken = async () => {
    const auth = Buffer.from(`${consumerKey}:${consumerSecret}`).toString('base64');
    const response = await axios.get(`${baseURL}/oauth/v1/generate?grant_type=client_credentials`, {
        headers: {
            Authorization: `Basic ${auth}`,
        }
    });
    return response.data.access_token;
};

const initiateMpesaPayment = async (phoneNumber, amount) => {
    const accessToken = await getAccessToken();
    const timestamp = new Date().toISOString().replace(/[-T:.Z]/g, '').slice(0, 14);
    const shortcode = process.env.SHORT_CODE;
    const passkey = process.env.PASSKEY;

    // The password is made up of the shortcode, passkey & timestamp
    const password = Buffer.from(`${shortcode}${passkey}${timestamp}`).toString('base64');

    // Payload which has all the required data for M-Pesa API structure
    const payload = {
        BusinessShortCode: shortcode,
        Password: password,
        Timestamp: timestamp,
        TransactionType: 'CustomerPayBillOnline',
        Amount: amount,
        PartyA: phoneNumber,
        PartyB: shortcode,
        PhoneNumber: phoneNumber,
        CallBackURL: process.env.CALLBACK_URL,
        AccountReference: 'Test123',
        TransactionDesc: 'Payment for services',
    };

    const response = await axios.post(`${baseURL}/mpesa/stkpush/v1/processrequest`, payload, {
        headers: {
            Authorization: `Bearer ${accessToken}`,
        }
    });
    console.log(response);
    console.log(response.data);
    return response.data;
};

// Test number from Daraja +254708374149
// Set amount
initiateMpesaPayment('+254708374149', 10);

export { initiateMpesaPayment };

// TODO: Error handling

Contributing

Feel free to open issues or submit pull requests if you have any improvements or bug fixes.

License

This project is licensed under the MIT License.

This README.md provides a comprehensive overview of your project, including installation instructions, usage guidelines, and code structure, making it easy for others to understand and contribute.

felixkamau / mpesa-express-backend