Fintech Payment API

A Payment API built with Spring Boot, using PostgreSQL, RabbitMQ, and Docker.

This project demonstrates an Event-Driven Architecture (EDA) where order creation generates events that are sent to a message broker and processed asynchronously.

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Technologies

• Java 21
• Spring Boot 3
• Spring Data JPA
• PostgreSQL
• RabbitMQ
• Docker
• Swagger / OpenAPI
• Lombok
• Maven

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Architecture

The system follows an Event-Driven Architecture using RabbitMQ for asynchronous communication.

It also follows a layered architecture, separating responsibilities into:

• Controllers
• Services
• Repositories

Project structure:

src/main/java/com/pay/payment_api
├── controller
├── service
├── repository
├── dto
├── mapper
├── entity
├── event
├── consume
└── exception

Application Flow

1. Client sends a request to create an order

2. The order is stored in PostgreSQL

3. An OrderCreatedEvent is published to RabbitMQ

4. A consumer receives and processes the event

Simplified flow:

Client → API → Database
              ↓
           RabbitMQ
              ↓
           Consumer

Features

• Create orders

• List orders

• Update order status

• Publish events to RabbitMQ

• Consume events asynchronously

• Global exception handling

• API documentation with Swagger

• Running the Project

1 Clone the repository
git clone https://github.com/marconi-prog/fintech-payment-api.git
cd fintech-payment-api

2 Start containers

docker compose up -d

This will start:

• PostgreSQL

• RabbitMQ

3 Run the application

mvn spring-boot:run

API Documentation

Swagger UI available at:

http://localhost:8080/swagger-ui/index.html

Endpoints Create Order

POST /orders

Request body:

{
  "customerId": "UUID",
  "amount": 100.50
}

List Orders

GET /orders

Update Order Status

PATCH /orders/{id}/status

Available status values:

PENDING

PAYMENT_PROCESSING

PAYMENT_APPROVED

PAYMENT_FAILED

Error Handling

The application includes a Global Exception Handler to standardize error responses.

Example response:

{
  "message": "Order not found",
  "status": 400,
  "timestamp": "2026-03-05T03:40:00"
}

Author

Marconi Farias Backend Developer