Second Brain

Second Brain is a full-stack personal knowledge management application for storing and organizing notes, tasks, tweets, and YouTube videos in one place.

Live: https://secondbrain.sbs

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Features

• Create and manage notes
• Track tasks and to-dos
• Save tweets for later reference
• Bookmark YouTube videos
• JWT-based authentication
• Google OAuth login
• Production deployment with HTTPS and custom domain

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Tech Stack

Frontend

• React
• Vite
• TypeScript
• React Router
• Axios

Backend

• Node.js
• Express
• TypeScript
• PostgreSQL (NeonDB)
• JWT Authentication
• Google Identity Services OAuth

Infrastructure & DevOps

• Docker
• Docker Compose
• Multi-stage Docker builds
• AWS EC2 (Ubuntu 22.04)
• Nginx reverse proxy
• SSL with Certbot
• Docker Hub image deployment pipeline

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Architecture

User Browser
     │
     ▼
https://secondbrain.sbs
     │
     ▼
AWS EC2 Instance
     │
     ├── Nginx (80/443)
     │     ├── /      → React Client Container
     │     └── /api   → Express Server Container
     │
     ├── Frontend Container (React + Vite)
     └── Backend Container (Node.js + Express)
                         │
                         ▼
                 NeonDB PostgreSQL

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Local Development

Prerequisites

• Node.js 20+
• Docker Desktop
• PostgreSQL or NeonDB

Clone the Repository

git clone https://github.com/compiler041/second-brain
cd second-brain

Install Dependencies

cd server && npm install
cd ../client && npm install

Environment Variables

Create server/.env

DATABASE_URL=your_database_url
JWT_SECRET=your_jwt_secret
GOOGLE_CLIENT_ID=your_google_client_id
PORT=3000

Create client/.env

VITE_API_URL=http://localhost:3000/api
VITE_GOOGLE_CLIENT_ID=your_google_client_id

Run Locally

Backend:

cd server
npm run dev

Frontend:

cd client
npm run dev

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Docker Setup

Build Backend

docker build \
  -t second-brain-server \
  -f docker/DockerFile.backend ./server

Build Frontend

docker build \
  --build-arg VITE_API_URL=http://localhost:3000/api \
  -t second-brain-client \
  -f docker/DockerFile.frontend ./client

Run Containers

docker-compose up -d

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Deployment Workflow

Build and Push Images

docker build \
  -t vaibhav0041/second-brain-server:vX \
  -f docker/DockerFile.backend ./server

docker push vaibhav0041/second-brain-server:vX

docker build \
  --build-arg VITE_API_URL=https://secondbrain.sbs/api \
  -t vaibhav0041/second-brain-client:vX \
  -f docker/DockerFile.frontend ./client

docker push vaibhav0041/second-brain-client:vX

Deploy on EC2

ssh -i key.pem ubuntu@your-ec2-ip

cd second-brain

docker-compose down
docker-compose pull
docker-compose up -d

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Engineering Learnings

• Reduced Docker image size from ~900MB to ~25MB using multi-stage builds
• Learned that Vite environment variables must be injected at build time
• Configured Nginx as a reverse proxy for frontend and backend routing
• Implemented connection pool error handling for NeonDB idle disconnects
• Configured React Router fallback routing using try_files
• Managed OAuth edge cases including duplicate username conflicts

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Production Issues Solved

Issue	Solution
React Router 404 errors on refresh	Added try_files $uri $uri/ /index.html in Nginx
Frontend calling localhost in production	Injected VITE_API_URL during Docker build
NeonDB idle connection crashes	Added pool-level and client-level error handling
OAuth duplicate key conflicts	Implemented email-first lookup and unique username generation
CORS failures during OAuth login	Configured production domain in backend and Google Console

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Future Improvements

• Add markdown editor for notes
• Add search and tagging system
• Add Redis caching
• Add CI/CD with GitHub Actions
• Add monitoring and centralized logging

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Author

Vaibhav Rathod

GitHub: https://github.com/compiler041 Live: https://secondbrain.sbs