99Tech Code Challenge - Full-Stack Engineer

This repository contains my submission for the Full-Stack Engineer technical challenge at 99Tech. Each challenge is organized in its respective directory with dedicated documentation and setup instructions.

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📂 Challenges Overview

#	Challenge	Focus Area	Status	Documentation
Problem 2	Fancy Form (Currency Swap)	Frontend / UI / State Management	Completed	README
Problem 4	Three ways to sum to $n$	Algorithms / TypeScript / Complexity	Completed	README
Problem 5	A Crude Server	Backend API / CRUD / Architecture	Completed	README
Problem 6	Architecture Specification	System Design / Security / Real-time	Completed	README

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🛠 Tech Stack Overview

• Runtime & Environment: Node.js (v24+ LTS) & TypeScript (v5+)
• Frontend: React 18, Vite 6, Custom Vanilla CSS Design System, Lucide Icons
• Backend: Express.js, SQLite with WAL Mode (better-sqlite3), Zod validation, Helmet, CORS, Morgan
• Architecture & System Design: Distributed Redis Cluster, WebSocket / SSE, PostgreSQL, Zero-Trust Action Tickets
• Tooling & Containerization: Docker (node:24-alpine), Docker Compose, Jest, Supertest

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🚀 Quick Start

Prerequisites

• Node.js (v24+ LTS recommended)
• Docker & Docker Compose (optional, if running containerized services)
• Package Manager: npm, yarn, or pnpm

Repository Structure

.
├── README.md                 # Root documentation (this file)
├── src/
│   ├── problem2/             # Interactive currency swap application
│   │   └── README.md
│   ├── problem4/             # Algorithm implementations (Three ways to sum to n)
│   │   └── README.md
│   ├── problem5/             # Backend service & CRUD APIs
│   │   └── README.md
│   └── problem6/             # System architecture & execution flow diagram
└── ...