Interview-Ready AI App

A full-stack web application to help users prepare for technical interviews using AI-powered question generation, timed practice sessions, and personalized session management.

Note: This project is under active development. Some features may be in progress or subject to change.

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Table of Contents

• Project Overview
• Screenshots
• Features
• Tech Stack
• Architecture
• API Reference
• Authentication Flow
• Environment Variables
• Setup & Run

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Project Overview

Interview-Ready AI App helps users prepare for technical interviews by:

• Creating and managing practice sessions
• Generating AI-powered interview questions and concept explanations (via Google Gemini)
• Pinning, noting, and reviewing questions per session
• Secure user authentication with profile picture support

The repo is split into two main folders:

• backend/ — TypeScript + Express API (controllers, services, Mongoose models, middlewares)
• frontend/ — React + Vite SPA (pages, components, Tailwind v4 styling)

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Screenshots

Landing Page

Application Interface

Learn More

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Features

• Authentication — Secure signup/login with HTTPOnly cookie JWTs, active session revocation on token reuse, and automatic token refresh.
• Security & Validation — Double-submit CSRF protection (csrf-csrf), strictly typed request validation via Zod, and full IDOR isolation across all tenants.
• Interactive Study Hub — Master questions with a visual progress bar, filter by "Pinned" or "Mastered" tabs, and reset session progress instantly.
• AI Assistance & Caching — Generate interview questions and concept explanations via Gemini API. Responses are cached via SHA-256 for performance.
• Transactions & Error Handling — MongoDB transactions for atomic inserts, global error normalization across all environments.
• Automated Testing — 20+ Vitest test suites covering core services, authentication flow, and AI retry logic.

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Tech Stack

Backend

Concern	Technology
Runtime	Node.js + TypeScript
Framework	Express v5
Database	MongoDB (Mongoose v8)
Auth	JWT (jsonwebtoken), bcryptjs, HTTPOnly cookies
Security	helmet, csrf-csrf, express-rate-limit, cors
AI	@google/genai (Google Gemini)
File Uploads	multer (buffer) + Cloudinary
Validation	Zod v4
Dev Tools	ts-node-dev, ESLint, Prettier, Vitest

Frontend

Concern	Technology
Framework	React v19 + TypeScript (Vite v6)
Styling	TailwindCSS v4 (@tailwindcss/vite)
Animations	Framer Motion v12
Routing	React Router DOM v7
HTTP	Axios (withCredentials: true)
Notifications	goey-toast
Icons	react-icons v5
Markdown	react-markdown, remark-gfm, react-syntax-highlighter
Validation	Zod v4

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Architecture

Backend Structure

backend/src/
├── index.ts              # Server entry — middleware stack, routes, error handler
├── config/
│   ├── db.ts             # MongoDB connection with retry
│   ├── serverConfig.ts   # helmet, cors, rate-limit configs
│   ├── csrf.ts           # csrf-csrf double-submit setup
│   └── cloudinary.ts     # Cloudinary SDK init
├── controllers/          # Request handlers (auth, ai, questions, sessions)
├── services/             # Business logic layer
├── models/               # Mongoose schemas (User, Question, Session)
├── middlewares/          # protect (JWT), requestLogger, validateRequest, upload
├── routes/               # Route definitions
├── schemas/              # Zod validation schemas
├── types/                # Shared TypeScript types
└── utils/                # env, AppError, catchAsync, errorHandler, responseHandler

Frontend Structure

frontend/src/
├── App.tsx               # Router + GoeyToaster
├── context/
│   └── userContext.tsx   # Global user auth state
├── pages/
│   ├── LandingPage/
│   ├── Auth/             # Login & Register forms
│   ├── Home/             # Dashboard
│   └── InterviewPrep/    # Active session page
├── components/           # Reusable UI (Navbar, Modal, Drawer, QuestionCard, etc.)
└── utils/
    ├── axios.ts          # Axios instance with CSRF + 401 refresh interceptors
    └── apiPaths.ts       # Centralized API path constants

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API Reference

Auth — /api/auth

Method	Path	Description	Auth
POST	/register	Create new user, sets cookies	—
POST	/login	Login, sets cookies	—
GET	/profile	Get current user profile	✅
POST	/logout	Clear auth cookies	✅
POST	/refresh	Rotate access token via refresh cookie	—
POST	/upload-image	Upload profile picture to Cloudinary	—

Sessions — /api/sessions

Method	Path	Description
POST	/create	Create a new practice session
GET	/my-sessions	List all sessions for current user
GET	/:id	Get session details
PATCH	/:id	Update session details
POST	/:id/reset-progress	Reset session mastery
DELETE	/:id	Delete a session

Questions — /api/questions

Method	Path	Description
POST	/add	Add question to a session
PATCH	/:id/pin	Pin or unpin a question
PATCH	/:id/note	Update personal note on a question
PATCH	/:id/status	Mark question as mastered/learning
DELETE	/:id	Delete question from session

AI — /api/ai

Method	Path	Description
POST	/generate-questions	Generate interview questions via Gemini
POST	/generate-explanation	Generate concept explanation via Gemini

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Authentication Flow

1. Login/Register → server sets two HTTPOnly cookies: accessToken (15 min) and refreshToken (7 days)
2. Requests — axios sends cookies automatically (withCredentials: true); non-GET requests include an x-csrf-token header
3. Token Refresh — on 401 response, axios interceptor calls POST /api/auth/refresh; if refresh fails, redirects to /
4. Logout — server clears both cookies; frontend clears user context

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Environment Variables

Backend (.env)

Variable	Default	Required
NODE_ENV	development	—
PORT	5000	—
MONGO_DB_URI	—	✅
ALLOWED_ORIGINS	http://localhost:5173	—
JWT_SECRET	—	✅
JWT_REFRESH_SECRET	(fallback set)	Recommended
GOOGLE_API_KEY	—	✅
GOOGLE_AI_MODEL	—	✅
CLOUDINARY_CLOUD_NAME	""	For image uploads
CLOUDINARY_API_KEY	""	For image uploads
CLOUDINARY_API_SECRET	""	For image uploads
IS_PROD	false	—

Frontend (.env.local)

Variable	Purpose
VITE_BASE_URL	Backend API base URL (e.g. http://localhost:5000)

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Setup & Run

Backend

cd backend
npm install
npm run dev        # starts on http://localhost:5000

Frontend

cd frontend
npm install
npm run dev        # starts on http://localhost:5173

Other scripts

npm run build       # production build
npm run type-check  # TypeScript check (backend)
npm run lint        # ESLint
npm run format      # Prettier