$ ssh sajib@portfolio

Welcome to SajibOS: backend engineering environment

ShahadathHossenSajib

Backend engineer building microservices and AI powered systems with Node.js, TypeScript, and Python. Writes about them after midnight. You are welcome to deploy.

GitHub Profile View Resume

whoami

the human behind the shell. Takes systems from schema to production and keeps them there.

I’m a backend engineer who builds distributed systems and AI-powered services. Coming from full-stack work, I design APIs around what the frontend actually needs: pagination, loading states, and error handling you can build on.

If it has an endpoint, I wrote it, documented it, and probably got paged for it once.

I deploy what I build: Docker on AWS, CI/CD pipelines, Linux boxes behind Nginx or Caddy. I optimize for boring, observable systems that are easy to debug at 2am. Production is the deliverable.

ownership.serviceactive

End-to-end ownership

Schema to production, deployment and runtime included. One thread of ownership, no handoff gaps.

arch.serviceactive

Microservices & contracts

Clear boundaries, strong contracts, async patterns that decouple services and absorb load. Boring architecture on purpose.

ai.serviceactive

AI in production

RAG pipelines, tool calling, and vector search serving real users, not demos. Plus real-time tracking at product scale.

ops.serviceactive

CI/CD & operations

Pipelines and AWS deploys that are smooth and reversible, with monitoring that catches issues before users do.

stack --list

Installed packages, refreshed often. Backend systems that reach production: languages, frameworks, data layers, AI tooling, and the delivery pipeline that carries them.

languages

TypeScript·JavaScript (ES6+)·Python

TypeScript-first for type-safe backends; Python for AI, automation, and FastAPI services.

backend

Node.js·NestJS·FastAPI·Express.js

Node.js/NestJS for real-time and modular services; FastAPI for ML and async workloads.

databases

PostgreSQL·MongoDB·Redis

Polyglot persistence, relational, document, and in-memory stores chosen per workload.

orm / odm

Prisma·Mongoose·Drizzle

Typed data layers with Prisma and Drizzle; Mongoose for document models.

cloud & devops

Docker·AWS (EC2, S3)·Nginx·Caddy·GitHub Actions

Containerized deployments on AWS, automated through CI/CD and reverse-proxied on Linux.

realtime

Socket.IO·WebRTC·BullMQ·Redis Pub/Sub·mediamtx

Live streaming (RTMP → HLS via mediamtx), signaling, and queue-driven background processing at product scale.

ai & llm

OpenAI API·Ollama·RAG·Vector Search

Production AI features, RAG pipelines, tool calling, and vector search over self-hosted or OpenAI models.

security & auth

JWT·OAuth 2.0·2FA & OTP·RBAC

Auth flows shipped to production, JWT, Google OAuth with JWKS verification, Redis-backed OTP, 2FA, and RBAC.

uptime --log

three shops, a lot of shipped services. The uptime log.

Back End Developer

Digital PylotDhaka, Bangladesh · On-site

Feb 2026 - Present

Shipped AI features on a large-scale CRM/CMS microservices platform, custom RAG chatbot, tool calling, document retrieval, and workflow automation, backend to deployment.
Built a fully customizable CMS, admins manage themes, layouts, pages, and dynamic content with zero code changes, cutting content-ops turnaround to minutes.
Developed REST APIs on PostgreSQL and MongoDB with dynamic configuration and role-based notifications driving complex business workflows.
Runs on Linux VPS: Nginx, SSL, CI/CD, deployed, monitored, and kept the microservices honest.

Back End Developer

Softvence AgencyDhaka, Bangladesh · On-site

Jul 2025 - Feb 2026

Engineered a platform-level payment engine, subscriptions, promo codes, and rule-based automated payouts moving real money, on time.
Built Uber-style real-time logistics tracking, dynamic multi-party routing that adapts to live weather.
Automated HR and payroll workflows, timezone-aware scheduling, activity streams, and location-aware map services.
Shipped AI automation, candidate evaluation, interview generation, and contextual analytics.
Owned PostgreSQL schemas (Prisma/Drizzle), Redis caching, and AWS EC2 + S3, with monitoring to prove it.

Web Developer

Monster StudioChattogram, Bangladesh · On-site

Aug 2024 - Apr 2025

Shipped features across a monorepo powering 20+ production websites, responsive, SEO-optimized, and fast.
Built an AI document assistant with retrieval-based, context-aware answers.
Created internal tools, custom CMS and creator utilities wired to external APIs like YouTube.
Led a frontend team through code reviews and task coordination, better reviews, faster delivery.
Hardened reliability with unit and performance tests across projects.

ls ~/deployed

Things running in production, not just sitting in repos.

All Repos

adda

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Full-stack monorepo, FastAPI backend, React 19 + TypeScript frontend, mediamtx streaming server, single Docker Compose deploy
Live streaming pipeline: RTMP ingest → HLS playback with per-community stream keys, publish-auth webhooks, and auto-recordings
Real-time layer, WebSocket gateway with typed protocol, Redis pub/sub fan-out for multi-instance scaling, and presence tracking
Complete auth suite: JWT, Google OAuth, passwordless OTP login (Redis-backed), 2FA, and RBAC roles

voice-to-text

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AI transcription service built on OpenAI Whisper, usable as a CLI tool or a FastAPI REST server
Speaker diarization (SpeechBrain embeddings) labels who spoke what; non-English audio translates to English
Fully local, audio never leaves the machine; pluggable Whisper backends (OpenAI or Hugging Face)
One-command Docker deployment, Pydantic v2 validation, Ruff/MyPy/Bandit quality gates with CI

systemix

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A "standard library" for modern Node.js, 7 packages published to npm and GitHub Packages
Cryptographically secure generators: passwords with character guarantees, passphrases, and signed tokens (hex/base64) built on Node crypto
Typed env loading and validation, shareable ESLint 10 flat configs, TypeScript bases, and a minimal test runner
Turborepo + pnpm monorepo, tsup bundling, full type safety, built for both small projects and large monorepos

git log --activity

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tail -f thoughts.log

Long-form notes on backend architecture and API design, mostly written past midnight.

All on Medium

ping sajib

Email works great for a direct line. Prefer a structured collaboration? I'm active on open source communities and platforms like GitHub. I read every packet, and reply to most.

Drop me an email

Send me a message for collaborations, inquiries, or just a friendly chat. I typically respond within 24 hours.

shahadathhossensajib732@gmail.com

Send Email

Resume

Check out my professional journey and technical stack in detail.

View Resume

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