MindVault — AI-Powered Journal Management System

MindVault is a secure, AI-powered journal management backend built with Java 17 and Spring Boot 3. Users can create private journal entries that are asynchronously analyzed by Google Gemini Flash API to generate mood sentiment scores (POSITIVE / NEGATIVE / NEUTRAL), delivered via an Apache Kafka pipeline.

Features

• JWT-based authentication with role-based access control (USER / ADMIN)
• Full CRUD for personal journal records
• Asynchronous AI sentiment analysis via Google Gemini Flash 2.0 API
• Apache Kafka event pipeline for non-blocking mood processing
• Local lexicon fallback when Gemini API is unavailable
• Redis caching for session and frequently accessed data
• Weekly mood trend analytics endpoint
• Journal entry search and tag filtering
• Streak tracking — consecutive days journaled
• CORS configuration, input validation, global exception handling
• CI/CD via GitHub Actions

Tech Stack

Layer	Technology
Language	Java 17
Framework	Spring Boot 3, Spring Security
Database	MongoDB
Cache	Redis
Message Queue	Apache Kafka
AI	Google Gemini Flash 2.0 API
Auth	JWT, BCrypt
DevOps	GitHub Actions CI/CD

API Endpoints

Method	Endpoint	Auth	Description
POST	/api/auth/signup	Public	Register new account
POST	/api/auth/login	Public	Login, returns JWT token
GET	/api/entries	USER	Get all journal records
POST	/api/entries	USER	Create journal entry
GET	/api/entries/{id}	USER	Get single entry
PUT	/api/entries/{id}	USER	Update entry
DELETE	/api/entries/{id}	USER	Delete entry
GET	/api/entries/{id}/mood	USER	Get AI sentiment for entry
GET	/api/entries/search?q=	USER	Search entries by keyword
GET	/api/analytics/mood-trend	USER	Weekly mood summary
GET	/api/analytics/streak	USER	Journaling streak count
GET	/api/admin/accounts	ADMIN	Get all user accounts

Getting Started

Prerequisites

• Java 17+
• MongoDB (local or Atlas)
• Redis (optional)
• Apache Kafka (optional — sentiment falls back to lexicon)
• Google Gemini API key (free tier at aistudio.google.com)

Setup

git clone https://github.com/Chinmay0608/journalApp.git
cd journalApp
cp .env.example .env
# Fill in your values in .env
mvn spring-boot:run

Architecture

Client → Spring Boot REST API → MongoDB
              ↓
        Kafka Producer
              ↓
        Kafka Consumer
              ↓
    Gemini Flash 2.0 API → Mood Score → MongoDB
    (fallback: Local Lexicon)
              ↓
        Redis Cache

Author

Chinmay Maheshwari LinkedIn | GitHub