2025 Google Developer Groups APAC Solution Challenge – Todak 프로젝트 회고

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2025년 초, 약 2개월에 걸쳐 진행된
Google Developer Groups APAC Solution Challenge에 참가하며
‘Todak(토닥)’이라는 감정 케어 서비스 프로젝트를 완성하게 되었습니다.

이번 글에서는 서비스의 기획부터 개발, 배포까지
실제 구현 과정을 간단히 소개하고, 제가 맡은 역할을 정리해보려 합니다.

AI-Powered Emotional Support Diary "Todak"

Todak(토닥) is an innovative, private diary service (Closed-Type SNS) where users can freely express their emotions while receiving AI-powered empathetic responses.

Overview

In modern society, many people lack a safe and private space to express their emotions and receive emotional support. It's often difficult to openly share personal feelings with others, leading to emotional isolation and stress. Todak creates a warm, supportive environment where individuals can freely share their feelings and feel genuinely understood through AI-powered emotional support.

Our solution was developed for the APAC Solution Challenge to address this critical emotional well-being need.

The name "토닥" in Korean means to gently pat someone to offer comfort or emotional support - perfectly capturing the essence of our service.

🎥 Demo Video

🏗️ System Architecture

A web application architecture diagram showing a monolithic Spring Boot application deployed in multiple instances for rolling updates within a Kubernetes cluster, featuring client-side Vue.js and React, a shared MySQL database

🖼️ Use Case Diagram

The following diagram illustrates the main interactions and relationships between users, AI friends, and the system

🎯 Key Features

✍️ 1. Private Diary Writing

Users can freely write and store their emotions in a closed, secure environment that encourages honest emotional expression without fear of judgment.

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🤖 2. AI Empathy Companion

Our AI, "토닥이" reads diary entries and generates personalized, empathetic comments that feel like support from a warm, understanding friend.

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🧬 3. MBTI-Based AI Responses

AI provides empathetic and comforting comments based on the diary written by the user, based on one of the 16 MBTI personality types.

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🕵️‍♀️ 4. Anonymous Comment Function

Based on the diary written by the user, users registered as friends and AI can comment. All comments by users and AI are provided anonymously, and anonymity can be deactivated through points.

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🌱 5. Emotion Growth Visualization

A virtual tree on the main screen grows as users consistently write in their diary, symbolizing emotional growth and encouraging continuous engagement through visual feedback.

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👫 6. Friend Features

Users can access friends' diaries and guestbooks (with permission) and write comments to support each other, creating a community of emotional support.

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💎 7. Points System

Users can earn points by checking in daily, writing in a journal, and leaving comments, which can be used to grow the tree and unlock visual progress milestones. Anonymous comments can also be unlocked.

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📡 8. Real-Time Notifications

The system alerts users when someone comments on their diary or guestbook, implemented using lightweight Server-Sent Events (SSE) and Redis Streams for efficient real-time communication.

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🔧 9. Admin Dashboard

Built with Thymeleaf, the admin dashboard offers dynamic filtering and management by user, date, and status for effective platform oversight.

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📊 10. Monitoring and Logging

The backend is monitored using Prometheus and Grafana, with error logs stored per user for analysis and stability improvement.

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📁 Repository

👉 FE Github Repository

👉 BE Github Repository

🛠️ Tech Spec

💻 Frontend

⚙️ Backend

📊 Monitoring

🗃️ ERD

Server Entity Relationship Diagram

👥 Team Todak

This project was developed by Team Todak to participate in the APAC Solution Challenge.
We aim to create a warm service that provides emotional support and emotional stability through technology.

👤 My Role — Engineering the Heartbeat of Todak

As the Team Lead and Backend Architect, I played a pivotal role in transforming Todak from an idea into a fully deployed, emotionally intelligent platform.
My responsibilities spanned across both technical leadership and hands-on development, including:

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🚀 System & Architecture Design

• Designed a scalable web application architecture using Spring Boot with Kubernetes for high availability and rolling updates.

🔧 DevOps & Infrastructure

• Built and managed CI/CD pipelines for seamless and automated deployment.
• Maintained and secured production server environments using best practices.

📡 Monitoring & Observability

• Integrated Prometheus & Grafana for real-time monitoring and analytics.
• Implemented detailed user-specific error logging for precise debugging and stability.

💡 Core Backend Development

Led the implementation of mission-critical business features that power the emotional intelligence of Todak:

• 🌳 Emotion Tree Growth System
  → Visualizes emotional progress by growing a virtual tree as users engage

• 📔 Diary System
  → Enables secure, anonymous emotional expression in a private space

• 👫 Friendship Features
  → Allows users to view friends’ diaries and guestbooks, and exchange supportive comments

• 🕵️‍♂️ Anonymous Interaction Module
  → Supports anonymous posting, which can be unlocked using points

• 💎 Point & Lock Mechanism
  → Encourages engagement with a gamified experience and unlockable features

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I combined technical excellence with empathy-driven engineering to build a platform that truly understands and supports its users.

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📂 GitHub Profile: https://github.com/GitJIHO