# Tanzim Hossain

**Backend Engineer** | TypeScript · Java · System Design

tanzimhossain2@gmail.com  
+88 01838647383  
Dhaka, Bangladesh  
https://github.com/0xtanzim  
https://linkedin.com/in/0xtanzim

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## Professional Summary

Backend Engineer focused on multi-tenant SaaS systems using TypeScript (Node.js) and Java (Spring Boot). I care about clean data models, concurrency-safe booking/scheduling logic, and REST API design that holds up in production.

## Experience

### Backend Engineer & Mentor — Softsasi
_Jun 2025 — Present · Full-time · Remote_

- Designed backend services, API contracts, and PostgreSQL data models
- Built modular REST APIs with clear domain boundaries
- Contributed to architecture reviews and design decisions
- Mentored developers through code reviews and engineering guidance

## Selected Projects

### Salon Management SaaS — Multi-tenant SaaS Platform
_2025 · Active_

Multi-tenant salon booking platform, built solo end-to-end. 27 domain modules across 110+ tables. Booking writes are protected by a pessimistic row lock plus a partial unique index as a hard backstop; a separate Redis mutex guards the temporary slot-hold cache. Caught and fixed a real production billing bug where two disconnected settings quietly disagreed on the platform's cut of every booking. Live at donebyme.dk.

**Stack:** TypeScript • Next.js • NestJS • PostgreSQL • Drizzle ORM • Redis • Google Maps API • PostGIS • Stripe • Capacitor • AWS EC2 • Nginx • pnpm Turborepo

### FileTree Pro — VS Code Extension
_2025 · Active_

VS Code extension to preview and generate project folder trees before files hit disk. 36,000+ installs on the Marketplace, 5.0 average rating. Conflict-aware by design — existing files are never silently overwritten.

**Stack:** TypeScript • VS Code API • Webview UI
**Impact:** 36,000+ downloads

### NextRush — Backend Framework
_2025 · In Progress_

A TypeScript backend framework monorepo — 20+ packages covering a segment-trie router, a tsyringe-wrapped DI layer, Koa-style middleware, and Node/Bun/Deno/Edge adapters. Benchmarked with autocannon against Fastify, Express, Koa, and Hono: 14% overhead vs raw Node.js, and it wins the middleware-stack scenario outright (32,220 RPS vs Fastify's 28,744).

**Stack:** Node.js • TypeScript • tsyringe • Bun • Deno

## Technical Skills

- **Backend:** Node.js, NestJS, Spring Boot
- **Database:** PostgreSQL, Redis, MongoDB
- **Architecture:** Multi-Tenant Architecture, Clean Architecture, Framework Design
- **System Design:** Caching, Concurrency Control
- **Infrastructure:** AWS, Docker
- **Languages:** TypeScript, Java, Go
- **AI:** LLM Integration, LangChain

## Achievements

### NASA International Space Apps 2025 — Climaxplore (Team Softsasi)
_2025 · 1st Runner Up_

1st Runner-up, NASA Space Apps Challenge 2025 (Mymensingh) — architecture support for Climaxplore, an AI weather-risk platform.

### Google Chrome Built-in AI Challenge 2025 — ContentChat AI
_2025 · Built-in AI Challenge_

Built ContentChat AI using on-device Gemini Nano — Chrome Built-in AI Challenge 2025.

## Education

- **BSc in Computer Science** — United International University (UIU) _(Ongoing)_