💰 Ledger - Smart Expense Tracker with AI Insights

A full-stack expense tracker built with Java Spring Boot. Ledger lets users record expenses, review spending patterns, and get AI-powered category suggestions and financial insights from Groq.

Demo and availability

The live Render deployment is currently unavailable. The link below is a recorded walkthrough, so it shows the app but does not provide a live app to use. To try Ledger interactively, follow the local setup instructions below.

Watch the recorded demo

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🚀 Features

• Add and manage expenses with preset or custom categories
• Automatic category suggestions suggests a preset category from the description; you can change it
• Google login each user sees only their own data
• Monthly and yearly views with spending totals and comparisons
• Charts for category breakdown and monthly trends
• AI Insights with spending patterns and savings suggestions
• MySQL database data persists across sessions

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🛠 Tech Stack

Layer	Technology
Backend	Java 17, Spring Boot 4.0.6, Spring Data JPA
Database	MySQL
Frontend	HTML, CSS, Vanilla JavaScript
Auth	Spring Security + Google OAuth2
Charts	Chart.js
AI	Groq API (model configured with groq.model; defaults to openai/gpt-oss-120b)
Architecture	MVC — Controller → Service → Repository

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⚙️ Setup Instructions

Prerequisites

• Java 17+
• MySQL
• Groq API key (free at console.groq.com)

Steps

1. Clone the repository

git clone https://github.com/Krshm10/Ledger.git
cd Ledger

2. Create MySQL database

CREATE DATABASE expensedb;

3. Configure application.properties

Copy the example file, then fill in your MySQL, Groq, and Google OAuth credentials:

cp src/main/resources/application.properties.example src/main/resources/application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/expensedb
spring.datasource.username=root
spring.datasource.password=YOUR_MYSQL_PASSWORD

groq.api.key=YOUR_GROQ_API_KEY
# Optional; defaults to openai/gpt-oss-120b
groq.model=openai/gpt-oss-120b

spring.security.oauth2.client.registration.google.client-id=YOUR_GOOGLE_CLIENT_ID
spring.security.oauth2.client.registration.google.client-secret=YOUR_GOOGLE_CLIENT_SECRET

server.port=8080
spring.web.resources.static-locations=classpath:/static/

For Google login, create an OAuth client ID in the Google Cloud Console. Add this authorized redirect URI: http://localhost:8080/login/oauth2/code/google.

Category suggestions and AI Insights use the same Groq key and model. Suggestions use the app's existing preset categories. If Groq is unavailable or returns an unrecognized category, the form keeps its current selection and lets you choose a category yourself.

4. Run the application

.\mvnw.cmd spring-boot:run

5. Open Ledger in your browser

http://localhost:8080/index.html