Finance Tracker Backend

Spring Boot REST API for managing financial data

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Overview

This is a personal project made by me. It is a Spring Boot based backend application, that provides RESTFul APIs for managing financial data, including users, accounts, transactions, categories, budgets and exchange_rates. This application is built on top of a pre-designed relational database made with PostgreSQL.

This project was built mainly to get hands-on experience with a database management system like Postgres and Spring Boot to build production-style backend APIs.

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Scope

This application can:

• Providing CRUD functionalities over the finance-tracker database.
• Validating and persisting financial data
• Handling CSV-based bulk transactional imports
• Performing currency-conversion using an external exchange-rate data

What's out of scope for this project (for now) is:

• User-facing front-end
• Authentication beyond basic credential handling
• Financial analytics, forecasting or analytics

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Features

• CRUD operations for users, accounts, categories, transactions, and budgets
• CSV upload endpoints for bulk transaction imports, with duplicate detection and import_batch tracking
• Currency conversion using ExchangeRate-API
• RESTFul API design with clear resource boundaries
• Validation and basic error-handling for incoming requests

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Tech Stack

• Java 21
• Spring Boot
• PostgreSQL
• ExchangeRate-API
• Maven

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Database Design

The full database design, including:

• Entity definitions
• Relationships
• Constraints and indexes
• Design decisions and limitations

can be found in this document

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API Overview

The application provides RESTFul endpoints for the following resources:

• /users
• /accounts
• /categories
• /transactions
• /budgets
• /import-batches
• /exchange-rates

All endpoints accept and return JSON.

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CSV Import

This application has an endpoint to upload CSV files containing transactions-related data. Its key behaviours are:

• Transactions are processed in an import batch
• A record of total, successful and failed imports are kept per batch
• Duplicate transactions are skipped and counted as a failed transaction
• Errors during processing are captured per batch

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Configuration and Setup

The application requires the following environment variables

• Database connection credentials (SPRING_DATASOURCE_PASSWORD, SPRING_DATASOURCE_USERNAME)
• ExchangeRate API Key (EXCHANGERATE_API_KEY)

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Running the Application

1. Clone the repository
2. Configure the database and the above mentioned API Keys
3. Run the application with

  mvn spring-boot:run

The API will be available at http://localhost:8080

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Limitations and Future Work

• No support for recurring transactions
• No real-time exchange rate updates
• Limited authentication and authorisation
• No audit logging for data changes