LevelUp.io — Intelligent Interview Preparation Platform

React Express PostgreSQL Socket.IO Claude AI License

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

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Features · Quick Start · API Reference · Architecture · Dataset

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

Name		Name	Last commit message	Last commit date
backend		backend
frontend		frontend
README.md		README.md

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LevelUp.io — Intelligent Interview Preparation Platform

Table of Contents

Features

Tech Stack

Frontend

Backend

Project Structure

Getting Started

Prerequisites

1. Clone the repository

2. Install dependencies

3. Configure environment variables

4. Run database migrations

5. Start all servers

Environment Variables

API Reference

Auth

Sessions

Problems

AI Interview

Performance

Socket.IO Events

User Roles

Database Schema

Scripts

Backend

Frontend

License

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