LevelUp.io — Intelligent Interview Preparation Platform

Enterprise-grade technical interview platform powered by AI.
Real-time collaborative coding, AI-scored mock interviews, and 250+ curated problems — all in one place.

🌐 Live Demo

Features · Quick Start · API Reference · Architecture · Dataset

---

Table of Contents

• Features
• Tech Stack
• Project Structure
• Getting Started
• Environment Variables
• API Reference
• Socket.IO Events
• User Roles
• Database Schema
• Scripts
• License

---

Features

• AI Mock Interviews — Conversational AI interviewer powered by Claude evaluates answers and returns scored feedback with grades, strengths, and improvement suggestions
• Invite-Only Live Rooms — Interviewers create private sessions and invite candidates by username; only invited users can see and join their session
• Real-Time Collaboration — Shared Monaco editor powered by Yjs/CRDT with live cursors, language switching, and instant in-browser code execution
• 250+ Curated Problems — NeetCode 250 synced from LeetCode with difficulty filters, tag search, and pagination
• Performance Analytics — Visual charts tracking AI interview scores over time by topic and grade
• User Profile Management — Dedicated profile page where users can view their account info, change their password, and permanently delete their account
• Role-Based Access Control — Distinct permission flows for Candidates, Interviewers, and Admins
• Secure Authentication — JWT + httpOnly cookies, email verification, and password reset via email link

---

Tech Stack

Frontend

Technology	Purpose
React 19 + Vite	UI framework and build tooling
React Router v7	Client-side routing
Tailwind CSS v4	Utility-first styling with custom design tokens
Monaco Editor	Code editor (same engine as VS Code)
Yjs + y-websocket	CRDT-based real-time collaborative editing
Socket.IO Client	Live room events (join, chat, code sync, problem selection)
Axios	HTTP client with JWT interceptors
React Hook Form	Form state management

Backend

Technology	Purpose
Express 5	HTTP server and REST API
Prisma 7 + PostgreSQL	ORM and relational database
Socket.IO	WebSocket server for live rooms
y-websocket	Yjs WebSocket provider for collaborative editing
Anthropic SDK (Claude)	AI interview evaluation and feedback
bcrypt + JWT	Password hashing and stateless authentication
Zod	Request validation schemas
Redis (ioredis)	Caching layer for problems and pending registrations
Nodemailer + Brevo	Transactional email (verification, password reset)
Jest + Supertest	Unit and integration testing

---

Project Structure

ai-interview-platform/
├── backend/
│   ├── config/
│   │   ├── config.js           # Environment variables
│   │   ├── database.js         # Prisma client
│   │   └── redis.js            # Redis connection
│   ├── controllers/
│   │   ├── authController.js   # Register, login, password, profile
│   │   ├── sessionController.js
│   │   ├── problemController.js
│   │   ├── aiController.js
│   │   └── performanceController.js
│   ├── middleware/
│   │   ├── auth.js             # JWT verify + role-based access
│   │   ├── validate.js         # Zod request validation
│   │   ├── errorHandler.js
│   │   ├── asyncHandler.js
│   │   └── rateLimit.js
│   ├── prisma/
│   │   ├── schema.prisma       # Database models
│   │   └── migrations/
│   ├── routes/
│   │   ├── index.js
│   │   ├── authRoutes.js
│   │   ├── sessionRoutes.js
│   │   ├── problemRoutes.js
│   │   ├── aiRoutes.js
│   │   └── performanceRoutes.js
│   ├── services/
│   │   ├── aiService.js        # Claude API integration
│   │   ├── emailService.js     # Verification + reset emails
│   │   └── cacheService.js     # Redis helpers
│   ├── sockets/
│   │   └── roomHandler.js      # Socket.IO room event listeners
│   ├── utils/
│   │   ├── jwt.js
│   │   ├── validators.js       # Zod schemas
│   │   └── apiResponse.js      # Standardized response format
│   └── index.js                # Server entry point
│
└── frontend/
    └── src/
        ├── api/
        │   └── axios.js        # Axios instance with auth interceptors
        ├── components/
        │   ├── ProtectedRoute.jsx
        │   ├── SessionCard.jsx
        │   ├── SessionList.jsx
        │   └── PerformanceChart.jsx
        ├── context/
        │   └── AuthContext.jsx  # Global auth state
        └── pages/
            ├── Home.jsx
            ├── Login.jsx
            ├── Registar.jsx
            ├── VerifyEmail.jsx
            ├── ForgotPassword.jsx
            ├── ResetPassword.jsx
            ├── Dashboard.jsx
            ├── Profile.jsx
            └── LiveInterviewRoom.jsx

---

Getting Started

Prerequisites

• Node.js 18+
• PostgreSQL
• Redis
• An Anthropic API key
• A Brevo (Sendinblue) account for transactional email

1. Clone the repository

git clone https://github.com/your-username/levelup-io.git
cd levelup-io/ai-interview-platform

2. Install dependencies

# Backend
cd backend && npm install

# Frontend
cd ../frontend && npm install

3. Configure environment variables

Create a .env file inside the backend/ directory (see Environment Variables below).

4. Run database migrations

cd backend
npx prisma migrate deploy
npx prisma generate

5. Start all servers

Open three terminal tabs:

# Terminal 1 — REST API + Socket.IO (port 3000)
cd backend && npm run dev

# Terminal 2 — Yjs WebSocket server for collaborative editing (port 3001)
cd backend && npx y-websocket-server

# Terminal 3 — Vite frontend dev server (port 5173)
cd frontend && npm run dev

Open http://localhost:5173

---

Environment Variables

Create backend/.env with the following keys:

# Database
DATABASE_URL=postgresql://user:password@localhost:5432/levelup

# Server
PORT=3000
NODE_ENV=development

# Auth
JWT_SECRET=your_long_random_secret_here
JWT_EXPIRES_IN=7d
COOKIE_MAX_AGE=604800000

# Anthropic (Claude AI)
ANTHROPIC_API_KEY=sk-ant-...

# Redis
REDIS_URL=redis://localhost:6379

# Email (Brevo / Sendinblue)
BREVO_API_KEY=your_brevo_api_key
EMAIL_FROM=no-reply@yourdomain.com

# Frontend origin (for CORS + email links)
FRONTEND_URL=http://localhost:5173

Never commit your .env file. It is already listed in .gitignore.

---

API Reference

All endpoints are prefixed with /api/v1. Authenticated routes require a valid JWT either via Authorization: Bearer <token> header or the token httpOnly cookie set at login.

Auth

Method	Endpoint	Auth	Description
POST	/auth/register	—	Register — sends email verification link
GET	/auth/verify-email?token=	—	Verify email and activate account
POST	/auth/resend-verification	—	Resend verification email
POST	/auth/login	—	Login, returns JWT + sets httpOnly cookie
POST	/auth/logout	—	Clear auth cookie
GET	/auth/me	✓	Get current authenticated user
POST	/auth/forgot-password	—	Send password reset link to email
POST	/auth/reset-password	—	Reset password using token from email
PUT	/auth/change-password	✓	Change password (requires current password)
DELETE	/auth/delete-account	✓	Permanently delete account (requires password)

Sessions

Method	Endpoint	Role	Description
GET	/sessions	Any	List sessions (candidates see invitations only)
GET	/sessions/:id	Any	Get session by ID (access-controlled)
POST	/sessions	Interviewer / Admin	Create session and invite candidate by username
PUT	/sessions/:id	Interviewer / Admin	Update session status
DELETE	/sessions/:id	Admin	Delete session

Problems

Method	Endpoint	Auth	Description
GET	/problems	—	List problems (filters: difficulty, search, page, limit)
GET	/problems/:id	—	Get problem with test cases and starter code
POST	/problems/:id/run	✓	Run code against test cases (JavaScript sandbox)
POST	/problems/sync	✓	Sync NeetCode 250 from LeetCode into the database

AI Interview

Method	Endpoint	Auth	Description
POST	/ai/evaluate	✓	Submit answer for AI evaluation and scoring
GET	/ai/history	✓	Get past AI evaluation history

Performance

Method	Endpoint	Auth	Description
GET	/performance	✓	Get aggregate performance stats by topic and grade

---

Socket.IO Events

The live room connects to http://localhost:3000 with a JWT passed in auth.token.

Event	Direction	Description
join-room	Client → Server	Join a room (access checked against DB)
room-state	Server → Client	Full room state sent on successful join
room-error	Server → Client	Emitted when the user is not invited
user-joined	Server → Room	Broadcast when a participant joins
user-left	Server → Room	Broadcast on disconnect
code-change	Bidirectional	Real-time code sync (fallback to Yjs)
language-change	Bidirectional	Language switch sync across participants
chat-message	Bidirectional	Chat messages (last 100 kept in memory)
chat-typing	Client → Room	Typing indicator broadcast
select-problem	Client → Server	Interviewer selects a problem for the session
problem-selected	Server → Room	Broadcasts selected problem to all participants

---

User Roles

Role	Capabilities
CANDIDATE	AI mock interviews · Problem practice · View own invitations · Join invited rooms
INTERVIEWER	Everything above + Create sessions · Invite candidates by username · Select problems in room
ADMIN	Everything above + Delete sessions · View all sessions

---

Database Schema

User
  id, name, email (unique), username (unique), password, role
  resetToken?, resetTokenExpiry?
  createdAt, updatedAt
  → hostedSessions[], attendedSessions[], evaluations[]

InterviewSession
  id, title, role, level, status, scheduledAt
  interviewerId → User
  candidateId   → User

AIEvaluation
  id, userId, question, answer, role, level, topic
  score, grade, strengths[], improvements[], idealAnswer
  createdAt

Problem
  id, title, slug (unique), difficulty
  description, examples (JSON), constraints[], testCases (JSON)
  starterCode (JSON), tags[]

---

Scripts

Backend

npm run dev        # Start with nodemon (hot reload)
npm start          # Production start
npm test           # Run Jest test suite
npm run test:watch # Jest in watch mode

Frontend

npm run dev        # Vite dev server
npm run build      # Production build
npm run preview    # Preview production build locally
npm run lint       # ESLint

---

License

MIT