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5026 Mypatideepthi
5026 Mypatideepthi

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How I Built a Complete Invoice Management API with Spring Boot

#springboot #java #api #mysql

How I Built a Complete Invoice Management API with Spring Boot (And How You Can Too!)

SpringBoot #Java #API #InvoiceManagement #Backend #JWT #MySQL #WebDevelopment

πŸš€ Introduction

Building a production-ready API from scratch can take months. But what if you could get a complete, enterprise-grade Invoice Management API that's ready to use immediately?

In this post, I'll share how I built a comprehensive Invoice Management API using Spring Boot, and how you can get your hands on the complete source code to accelerate your own projects.

🎯 The Problem

When I started building invoice management systems for clients, I kept running into the same challenges:

  • Authentication complexity - JWT implementation, security best practices
  • Database design - Proper relationships, indexing, optimization
  • API documentation - Swagger setup, endpoint documentation
  • File handling - PDF generation, upload/download functionality
  • Error handling - Comprehensive validation and error responses
  • Testing - Unit tests, integration tests, test data

Each project took 3-4 months to build properly. That's when I realized - why not create a reusable solution?

πŸ› οΈ The Solution: Complete Invoice Management API

I built a production-ready Invoice Management API with Spring Boot that includes everything you need:

πŸ” Authentication & Security 

@RestController
@RequestMapping("/api/auth")
public class AuthController {

    @PostMapping("/signup")
    public ResponseEntity<?> registerUser(@Valid @RequestBody UserSignUpDTO signUpDTO) {
        // Complete user registration with validation
    }

    @PostMapping("/signin")
    public ResponseEntity<?> authenticateUser(@Valid @RequestBody UserLoginDTO loginDTO) {
        // JWT authentication with BCrypt password hashing
    }
}
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πŸ‘₯ User & Customer Management

  • Complete CRUD operations
  • Search functionality
  • Contact information management
  • Company association

πŸ“¦ Product Catalog

  • Product creation and management
  • Pricing with decimal precision
  • Search and filtering capabilities

🧾 Invoice System

  • Automatic invoice numbering
  • Line item management
  • Status tracking (draft, sent, paid, overdue)
  • Date range filtering

οΏ½οΏ½ Payment Tracking

  • Payment recording and linking
  • Payment history and audit trails
  • Total paid calculations

πŸ“„ PDF Generation

  • PDF creation from invoice data
  • File upload and download
  • Security and size limits

οΏ½οΏ½ Key Features

1. JWT Authentication 

@Component
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request, 
                                  HttpServletResponse response, 
                                  FilterChain filterChain) throws ServletException, IOException {
        // JWT token validation and authentication
    }
}
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2. Comprehensive API Documentation

The API includes Swagger/OpenAPI 3 documentation with:

  • Interactive API explorer
  • Request/response examples
  • Authentication documentation
  • Error code explanations

3. Advanced Search & Filtering 

@GetMapping("/search")
public ResponseEntity<List<CustomerDto>> searchCustomers(@RequestParam String query) {
    // Advanced search across multiple fields
}
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4. File Upload System 

@PostMapping("/{id}/pdf")
public ResponseEntity<?> uploadInvoicePdf(@PathVariable Long id, 
                                        @RequestParam("file") MultipartFile file) {
    // Secure file upload with validation
}
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πŸ› οΈ Technology Stack

Component Technology Version
Framework Spring Boot 3.4.5
Language Java 17
Database MySQL 8.0+
Security Spring Security + JWT Latest
Documentation Swagger/OpenAPI 3 2.7.0
PDF Processing Apache PDFBox 2.0.30

πŸ“Š API Endpoints Overview

The API provides 57+ endpoints across 7 modules:

Module Endpoints Description
Auth 5 endpoints Registration, login, profile management
Users 5 endpoints User CRUD operations
Customers 6 endpoints Customer management with search
Products 6 endpoints Product catalog management
Invoices 12 endpoints Complete invoice lifecycle
Payments 7 endpoints Payment tracking & management
Settings 3 endpoints User preferences

οΏ½οΏ½ Quick Start

1. Clone and Setup 

git clone https://github.com/MYPATIDEEPTHI/Invoice-management
cd Invoice-management
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2. Configure Database 

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/invoice_db
    username: your_username
    password: your_password
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3. Run the Application 

mvn clean install
mvn spring-boot:run
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4. Access the API

  • API Base: http://localhost:8080/api
  • Swagger Docs: http://localhost:8080/api/swagger-ui/index.html

🎯 Perfect Use Cases

This API is ideal for:

  1. SaaS Invoice Platforms - Complete backend for subscription services
  2. Freelancer Tools - Professional invoicing for contractors
  3. Small Business Management - Complete invoicing solution
  4. Learning Projects - Spring Boot best practices demonstration
  5. Portfolio Projects - Showcase enterprise-level development skills
  6. Startup MVPs - Quick backend for invoice management apps

πŸ’‘ What Makes This Special

Production Ready

  • βœ… Security best practices implemented
  • βœ… Comprehensive error handling
  • βœ… Input validation on all endpoints
  • βœ… Database optimization with proper indexing
  • βœ… API versioning structure ready

Developer Friendly

  • βœ… Clear code structure following Spring Boot conventions
  • βœ… Comprehensive documentation with examples
  • βœ… Easy setup with detailed installation guide
  • βœ… Testing framework with examples
  • βœ… Docker support for containerized deployment

Business Ready

  • βœ… Complete invoice workflow from creation to payment
  • βœ… Customer management with search capabilities
  • βœ… Product catalog for service tracking
  • βœ… Payment tracking with audit trails
  • βœ… PDF generation for professional invoices

🎁 Get the Complete Solution

Save 40+ hours of development time with this production-ready Invoice Management API.

What You'll Get:

  • βœ… Complete source code with 57+ endpoints
  • βœ… JWT authentication system with security best practices
  • βœ… Database models and repositories with proper relationships
  • βœ… Service layer with comprehensive business logic
  • βœ… Comprehensive documentation and installation guide
  • βœ… Frontend integration examples for React/Angular/Vue
  • βœ… Docker support for easy deployment
  • βœ… Testing framework with examples

Pricing:

  • πŸ’Ž Complete Solution: $29 (one-time purchase)

πŸ”— Links

πŸš€ Next Steps

  1. Download the free version from GitHub to explore the code
  2. Get the complete solution for $29 with full support
  3. Customize the API to fit your specific needs
  4. Build your frontend using the provided integration examples
  5. Deploy to production with the included Docker setup

πŸ’¬ Community

Have questions or need help?

  • πŸ“§ Email support for premium users
  • πŸ’¬ GitHub issues for the free version
  • πŸ“š Complete documentation included

πŸ‘¨β€οΏ½οΏ½ About the Author

I'm a full-stack developer with expertise in Spring Boot, React.js, TypeScript, and comprehensive testing. I built this API to help developers save time and focus on building great applications instead of reinventing the wheel.

My Tech Stack:

  • Backend: Spring Boot, Java, MySQL, JWT
  • Frontend: React.js, TypeScript, JavaScript, HTML, CSS
  • Testing: Manual testing, unit testing, integration testing
  • DevOps: Docker, deployment, CI/CD

This API represents months of real-world development experience and best practices I've learned building production applications.

🎯 Ready to Get Started?

Limited Time Offer: Get this complete Invoice Management API for just $29 and save 40+ hours of development time!

πŸ‘‰ Get the Complete Solution

What you'll get:

  • βœ… Complete source code with 57+ endpoints
  • βœ… JWT authentication with security best practices
  • βœ… Comprehensive documentation and setup guide
  • βœ… Docker support for easy deployment
  • βœ… Email support for any questions

Ready to build your next big thing? οΏ½οΏ½

This API provides everything you need to create a professional invoice management system. Whether you're building a SaaS platform, learning Spring Boot, or launching a startup, this codebase gives you a solid foundation to build upon.

Don't waste time building from scratch - get a production-ready solution that works!

What's your experience with building APIs from scratch? Have you ever wished you had a complete solution to start with? Share your thoughts in the comments below! πŸ‘‡

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