BankingAPI

A simple RESTful API built with Spring Boot to simulate basic banking operations like account creation and fund transfers.

Features

• Create user accounts with an initial balance
• Transfer funds between accounts
• Retrieve transaction history
• View all accounts
• Clean 3-layer architecture: Controller → Service → Repository

Tech Stack

• Java 21
• Spring Boot 3.4.4
• Spring Web

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User Guide

This project uses Gradle to build and run the Spring Boot application.

Prerequisites

Java 21 installed

Running the App (Dev Mode)

Clone the repo

git clone https://github.com/ireneboby/BankingAPI.git

Navigate to the project directory

cd BankingAPI

Run the app

./gradlew bootRun
The app will start on http://localhost:8080

Use Swagger to test API endpoints

Open in browser: http://localhost:8080/swagger-ui.html

To Build

Build the executable JAR file:

./gradlew clean build
This will generate a JAR file in the build/libs/ directory.

Run the JAR File

java -jar build/libs/<FILNAME>.jar

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API Endpoints

All endpoints return:

• 201 Created or 200 OK on success
• 400 Bad Request with an error message for invalid input (e.g. null fields, negative balance, insufficient funds)

Accounts

Create a new account

POST /api/accounts
Request Body: { "firstName": "Luna", "lastName": "Lovegood", "initialBalance": 1000.00 }

List All Accounts

GET /api/accounts
Returns a list of all account summaries.

Transactions

Transfer Funds

POST /api/transactions/transfer
Transfers funds between accounts.
Request Body: {"senderId": 1, "receiverId": 2, "transferAmount": 250.00}

Transaction History

GET /api/transactions/account/{accountId}
Returns a list of transactions where the account was a sender or receiver.

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Assumptions

• Account IDs are generated automatically using an in-memory counter
• Account Balances are handled using BigDecimal for currency precision
• No memory persistence yet — data is lost on app restart (in-memory only)
• No authentication or authorization is implemented
• Negative balances are not allowed
• Transaction history is not filtered (returns full history)
• Swagger is used as the only form of documentation
• Only basic validation is performed (e.g. null checks, amount > 0)
• Account names are not validated for uniqueness or formatting
• Currency is not supported (i.e. all amounts are assumed to be in a single currency like USD)