SkillLens AI — Backend

Production-ready Node.js + Express + MongoDB backend for the SkillLens AI interview preparation platform.

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Tech Stack

Layer	Technology
Runtime	Node.js 18+
Framework	Express 4
Database	MongoDB Atlas (via Mongoose 8)
Auth	JWT (jsonwebtoken) + bcryptjs
Security	Helmet, CORS
Dev tooling	nodemon, morgan

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Folder Structure

backend/
├── config/
│   └── db.js                  ← MongoDB Atlas connection
├── controllers/
│   ├── authController.js      ← register, login, profile, logout
│   └── dashboardController.js ← dynamic dashboard stats
├── middleware/
│   ├── auth.js                ← JWT protect + adminOnly
│   ├── errorHandler.js        ← global error handler
│   └── validate.js            ← required-field checker
├── models/
│   ├── User.js                ← user schema + password hashing
│   ├── Interview.js           ← interview session schema
│   ├── Resume.js              ← resume analysis schema
│   └── Result.js              ← AI feedback/score schema
├── routes/
│   ├── authRoutes.js          ← /api/auth/*
│   ├── dashboardRoutes.js     ← /api/dashboard
│   ├── interviewRoutes.js     ← /api/interview/* (Phase 5 stub)
│   └── resumeRoutes.js        ← /api/resume/*    (Phase 4 stub)
├── .env.example
├── package.json
└── server.js                  ← entry point

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Quick Start

1. Install dependencies

cd backend
npm install

2. Configure environment

cp .env.example .env
# Open .env and fill in your MONGO_URI and JWT_SECRET

Your .env should look like:

PORT=5000
NODE_ENV=development
MONGO_URI=mongodb+srv://skilllensadmin:SkillLens%402026@skilllens.0vjdlio.mongodb.net/?appName=SkillLens
JWT_SECRET=skilllens_super_secret_key
JWT_EXPIRES_IN=7d
CLIENT_URL=http://localhost:3000

3. Start development server

npm run dev

You should see:

✅  MongoDB connected: skilllens.0vjdlio.mongodb.net
🚀  SkillLens AI server running on port 5000
📡  Health: http://localhost:5000/health

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API Reference

Health Check

GET /health

Returns server + environment status. No auth required.

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Authentication /api/auth

Register

POST /api/auth/register
Content-Type: application/json

{
  "fullName": "Arjun Kumar",
  "email": "arjun@example.com",
  "password": "password123",
  "college": "IIT Delhi",
  "branch": "Computer Science",
  "year": 3
}

Returns: 201 with token + user object.

Login

POST /api/auth/login
Content-Type: application/json

{
  "email": "arjun@example.com",
  "password": "password123"
}

Returns: 200 with token + user object.

Get Profile (protected)

GET /api/auth/profile
Authorization: Bearer <token>

Update Profile (protected)

PUT /api/auth/profile
Authorization: Bearer <token>
Content-Type: application/json

{
  "college": "IIT Bombay",
  "year": 4
}

Logout (protected)

POST /api/auth/logout
Authorization: Bearer <token>

---

Dashboard /api/dashboard

Get Dashboard Stats (protected)

GET /api/dashboard
Authorization: Bearer <token>

Returns:

{
  "success": true,
  "data": {
    "totalInterviews": 27,
    "avgScore": 78,
    "resumeScore": 82,
    "improvementRate": 14,
    "recentActivity": [...]
  }
}

---

Postman Testing Guide

Step 1 — Register a new user

• Method: POST
• URL: http://localhost:5000/api/auth/register
• Body → raw → JSON:

{
  "fullName": "Test User",
  "email": "test@skilllens.com",
  "password": "test1234",
  "college": "IIT Delhi",
  "branch": "CSE",
  "year": 3
}

• Expected: 201 Created with token

Step 2 — Login

• Method: POST
• URL: http://localhost:5000/api/auth/login
• Body:

{
  "email": "test@skilllens.com",
  "password": "test1234"
}

• Copy the token from the response

Step 3 — Get Profile (protected)

• Method: GET
• URL: http://localhost:5000/api/auth/profile
• Headers: Authorization: Bearer <paste_token_here>
• Expected: 200 with user object

Step 4 — Dashboard

• Method: GET
• URL: http://localhost:5000/api/dashboard
• Headers: Authorization: Bearer <token>
• Expected: 200 with stats (all zeros until interviews exist)

Step 5 — Test error handling

• Call /api/auth/login with wrong password → expect 401
• Call /api/auth/profile with no token → expect 401
• Call /api/auth/register with duplicate email → expect 409

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Build Order

Phase	Feature	Status
1	Server + DB	✅ Done
2	Auth (register/login)	✅ Done
3	Dashboard API	✅ Done
4	Resume Analyzer	🔜 Next
5	HR Interview	🔜 Phase 5
6	Technical Interview	🔜 Phase 6
7	AI Feedback Engine	🔜 Phase 7
8	Analytics	🔜 Phase 8
9	Admin Panel	🔜 Phase 9

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Security Notes

• Passwords hashed with bcryptjs (12 salt rounds)
• JWT secret never exposed in responses
• password field excluded from all DB queries by default (select: false)
• Helmet sets secure HTTP headers
• CORS restricted to CLIENT_URL
• Mongoose validation on all models
• Global error handler catches Mongoose + JWT errors cleanly