Step-by-Step Build Order

Rebuilding the URL Shortener Engine from Scratch

Phase 1: Express 5 Foundation & Database Connection

1. Initialize modern ES module project ("type": "module" in backend/package.json).
2. Install express 5.1.0, mongoose 8.1.0, nanoid 5.1.5, dotenv, cors, cookie-parser.
3. Create backend/src/config/monogo.config.js with auto-reconnect listeners.
4. Setup backend/app.js with middleware chain and centralized error handler.

Phase 2: Schema Design & Data Access Object (DAO) Layer

1. Build backend/src/models/short_url.model.js with unique compound index on short_url.
2. Build backend/src/models/user.model.js with email uniqueness and bcrypt password hashing.
3. Implement backend/src/dao/short_url.js encapsulating saveShortUrl, getShortUrl, and atomic click increments.

Phase 3: Service Layer & Nanoid Logic

1. Implement backend/src/services/short_url.service.js with Nanoid 7-char generation.
2. Add custom slug conflict detection and reserved path filtering.

Phase 4: Controllers & Redirection Handlers

1. Build short_url.controller.js for /api/create and /:id HTTP 302 redirection.
2. Build auth.controller.js and user.controller.js.
3. Wire route modules in backend/src/routes/.

Phase 5: React 19 Frontend & State Management

1. Initialize Vite project with React 19 and Tailwind CSS v4.
2. Install @reduxjs/toolkit, react-redux, @tanstack/react-query, @tanstack/react-router.
3. Configure Axios client with withCredentials: true.
4. Build ShortenForm, UrlTable, and AnalyticsModal components.