PicPay Simplified Challenge

This repository contains the solution to the PicPay Back-end technical challenge – "PicPay Simplified". For study purposes, I chose to implement the application following Clean Architecture principles.

You can find the full challenge description in the repository above: https://github.com/PicPay/picpay-desafio-backend?tab=readme-ov-file

Technologies Used

• Java 17: A high-level, object-oriented programming language widely used for building server-side applications, web services, and Android applications.

• Spring Boot 3.5.3: A framework that simplifies the development of Java applications by providing built-in features for dependency injection, configuration, and microservices support.

• Spring Retry: Spring Retry is a module within the Spring framework that provides declarative retry support for Spring applications. Its primary purpose is to automatically re-invoke a failed operation, making applications more resilient to transient failures.

• H2 Database: H2 is an open-source lightweight Java database. It can be embedded in Java applications or run in the client-server mode.

• Jakarta Bean Validation: A standard framework for declaring and validating constraints on Java objects using annotations, commonly used to enforce business rules and input validation in a clean and declarative way.

• JPA: The Java Persistence API, a specification that provides object-relational mapping (ORM) to manage relational data in Java applications.

• Lombok 1.18.28: A Java library that reduces boilerplate code by generating common methods like getters, setters, constructors, and more through annotations.

• Postman: A tool used for API testing and development, enabling users to send HTTP requests, inspect responses, and automate API tests.

Requirements

To run the project on your machine, the following tools must be installed and configured beforehand:

• Java Development Kit (JDK) 17;
• Git;
• Postman (Optional for local development or testing).

Installation guide

Follow the steps below to download, configure, and run the project in your environment:

1. Clone the repository

git clone https://github.com/ABeatrizSC/picpay-simplified-challenge.git

2. Navigate to the project directory

cd picpay-simplified-challenge

3. Run the aplication

mvn spring-boot:run

API Endpoints

Users

GET /api/v1/users

• Deposits an amount to the user.

Success Response Body

• List<UserResponseDto>

[
  {
    "fullName": "John",
    "userType": "CUSTOMER",
    "email": "john@example.com"
  },
  {
    "fullName": "Alice",
    "userType": "MERCHANT",
    "email": "alice@example.com"
  }
]

POST /api/v1/users

• Create a new user.

Request Body

• UserCreateDto

{
  "fullName": "New user",
  "userType": "CUSTOMER", //user type: CUSTOMER or MERCHANT
  "document": "123.456.789-12",
  "email": "newuser@email.com",
  "password": "12345678"
}

Success Response Body

• 201 CREATED

POST /api/v1/users/deposits

• Deposits an amount to the user.

Request Body

• DepositFundsRequestDto

{
  "userId": "421b2925...",
  "amount": 50.0
}

Success Response Body

• User

{
  "id": "421b2925..",
  "fullName": "New user",
  "userType": "CUSTOMER",
  "document": "123.456.789-12",
  "email": "newuser@email.com",
  "password": "12345678",
  "balance": 50.00
}

Transactions

POST /api/v1/transactions

• Performs a transaction of values from one user to another.

Request Body

• TransactionRequestDto

{
  "amount": 50.0,
  "sender": "421...",
  "receiver": "cfe..."
}

Success Response Body

• 201 CREATED

Errors handled

Field validation error (MethodArgumentNotValidException)

{
  "status": 400,
  "error": "BAD_REQUEST",
  "message": "The field 'email' must not be blank."
}

Business rule violation (BusinessException)

• InsufficientBalanceException
• UnauthorizedTransactionException: Merchants are not allowed to perform transfers.

{
  "status": 500,
  "error": "INTERNAL_SERVER_ERROR",
  "message": "The available balance is insufficient to complete the transfer." //Variable
}

Transaction processing error (TransactionErrorException)

{
  "status": 500,
  "error": "INTERNAL_SERVER_ERROR",
  "message": "An error occurred during the transaction. Please try again."
}

Notification sending failure (NotificationSendException)

{
  "status": 500,
  "error": "INTERNAL_SERVER_ERROR",
  "message": "An error occurred while attempting to send the notification."
}

User not found (UserNotFoundException)

{
  "status": 404,
  "error": "NOT_FOUND",
  "message": "User not found." //Variable
}

Contact

• GitHub: ABeatrizSC
• Linkedin: Ana Beatriz Santucci Carmoni
• Email: anabeatrizscarmoni@gmail.com