Md. Junayed Bin Rafiq

Senior Backend & Full-Stack Engineer

I turn complex systems into reliable products.

I design the systems behind serious products—backend architecture, data flows, AI-enabled workflows, and the interfaces that make them useful. Across FinTech, global AdTech, enterprise document intelligence, and market analytics, I take complex ideas from architecture to production.

8+ years
Bangladesh
Remote-friendly

Explore work View GitHub Download CV

Living SystemsThe path I like to own: messy inputs become dependable state, useful intelligence, and finally a product people can trust.System online

Data Sources

Market feeds
Documents
Product events

APIs & Services

Domain APIs
Microservices
Integrations

Redis / PostgreSQL

Durable state
Caching
Async coordination

AI / Analysis

RAG
Decision support
Automated workflows

Product Experience

Web products
Operational tools
Clear decisions

Events & background processingKafkaTaskiqCI/CD

Featured case studies

From a complicated brief to something people can use.

Three chapters from the work: building a product end-to-end, creating reusable private AI infrastructure, and making financial systems feel dependable.

Stock Market Intelligence · Wealth Workspace · Independently built

StockWealthBD

A stock-market intelligence and personal-finance platform for Bangladesh—built to turn fragmented market data, analysis, and financial calculations into clearer decisions.

Designed the ingestion and caching flow that keeps market information coherent across live and finalised market states
Built stock analysis, scanners, signals, and decision-support experiences without hiding the underlying context
Connected portfolio tracking with wealth, tax-planning, and personal-finance tools
Owned the journey from product direction and architecture to production deployment with Docker, Nginx, and Cloudflare

Explore StockWealthBD

AI Platform Engine · Private knowledge

RAG Builder

A reusable private AI knowledge engine for products that need to understand their own resource.

Processes documents through parsing and OCR before preparing them for retrieval
Combines embeddings, vector search, retrieval, and RAG behind product-facing APIs
Supports LLM and embedding providers
Uses PostgreSQL and vector storage with Redis, background processing, and object storage

View RAG Builder

FinTech wallet interfaces for FastPay, NRB Click, BanglaPay, and Padma Wallet — Connected wallet productsFinTech & Wallet Platforms

Team-delivered · Security-sensitive systems

FinTech & Wallet Platforms

Backend work across banking, wallets, insurance payments, virtual cards, and fund-transfer integrations—delivered where correctness and security matter at every boundary.

Developed or contributed to mobile-banking and wallet backends for FastPay, NRB Click, BanglaPay, and Padma Wallet
Developed MetLife EFT payment automation and contributed to a VISA virtual-card system
Integrated bKash add-money and fund-transfer capabilities with IFIC Bank

FastPay NRB Click BanglaPay Padma Wallet

Engineering toolkit

Tools chosen for the job, not collected for a list.

Backend & services: Python · FastAPI · Django · PHP · Laravel · Node.js · NestJS · .NET Core · API design · Microservices
Data & platform: PostgreSQL · MySQL · MongoDB · Redis · Kafka · pgvector · MinIO · Docker · Nginx · AWS · Cloudflare · Jenkins · CI/CD · ELK Stack · CloudWatch · Observability
Product surfaces: Next.js · React · Vue.js · TypeScript · JavaScript · Testing · Agile delivery · Technical planning
AI & document intelligence: LLM integration · RAG systems · OCR · Embeddings · Vector search · Document workflows

Career journey

A career shaped by increasingly consequential systems.

The path runs from financial foundations through global scale and platform automation to products built independently.

01
Independent Builder
StockWealthBD & RAG
BuilderIndependent product work
After years of building inside product teams, I began owning the whole arc: choosing the problem, shaping the experience, designing the architecture, shipping it, and operating it. StockWealthBD and RAG Builder are where those disciplines meet.
- Product strategy
- FastAPI
- Next.js
- PostgreSQL
- Redis
- Docker
- RAG
02
May 2024 - Present
Platforms & Automation
FairpatternSenior Software Engineer
The work moved from transaction-heavy systems to document-heavy operations. I design backend services for an enterprise DMS and contribute to AI-assisted business-setup workflows involving document intelligence, LLM integration, and RAG-based assistance.
- Python
- FastAPI
- PostgreSQL
- Redis
- Kafka
- Docker
- Microservices
- LLM workflows
03
May 2022 - May 2024
Scale & AdTech
EskimiFull Stack Software Developer
At global AdTech scale, small inefficiencies become visible quickly. I contributed across Eskimi's DSP—from APIs and database-query optimisation to tests, logs, and Jenkins-driven releases.
- PHP
- Laravel
- MySQL
- Redis
- JavaScript
- Docker
- Jenkins
- ELK
04
January 2019 - April 2022
FinTech Foundations
SSL WirelessSoftware Engineer
FinTech became my engineering discipline. I worked on EFT automation, virtual-card security, mobile banking, wallets, and payment integrations where every request, state change, and handoff needed to be deliberate.
- Laravel
- .NET Core
- MySQL
- Redis
- React
- Vue.js
- AWS
- Payments
05
December 2017 - December 2018
Engineering Foundation
Bytelab LtdSoftware Engineer
I started with breadth: e-commerce, online ticketing, attendance systems, and client platforms. Moving between domains taught me to understand the workflow first and choose the technology second.
- PHP
- Laravel
- JavaScript
- Vue.js
- MySQL
- E-commerce
- Ticketing

Selected product references

The products behind the bullet points.

A closer look at systems across FinTech, AdTech, document operations, and ticketing—some public, some built for internal teams.

Insurance payments

MetLife EFT Payment

An enterprise EFT payment-processing solution for insurance operations, connecting the customer-facing flow with dependable backend handling.

Open MetLife EFT

Banking & wallets

Wallet Products

Backend contributions across mobile-banking and wallet products, including financial integrations, secure service handoffs, and transaction-oriented workflows.

FastPay NRB Click BanglaPay Padma Wallet

Global AdTech

Eskimi DSP

Full-stack contribution to Eskimi's global programmatic advertising platform, covering APIs, query performance, test coverage, observability, and production delivery.

Visit Eskimi DSP

Online ticketing

Soudia Bus Booking

Led the web application development for an online bus-booking product, turning route discovery and ticket purchase into a clearer digital journey.

Visit Soudia Bus

Enterprise document-management workflow visual

Document operations

Enterprise DMS

Microservice-oriented enterprise DMS with document workflows, asynchronous processing, document intelligence, and AI-assisted operations.

Abstract product-development visual combining online exams, e-commerce, scholarship results, retail, and pet-shop applications

Selected earlier work

Product Builds Across Domains

Earlier product delivery across online exams, microservice e-commerce, public-sector scholarship results, OASIS retail, and a pet-shop application—different domains connected by practical workflows and full-stack ownership.

Capabilities

Where the work has earned its depth.

These are patterns built through shipped products and teams—not percentage bars or a list of buzzwords.

API

Backend Systems

I design API-first systems with clear boundaries, durable data models, and background work that stays understandable as the product grows—from caching and async flows to deployment, observability, and repeatable releases.

System problems: Complex business rules, service boundaries, integrations, data consistency, production visibility, delivery pipelines, and maintainable change.
Evidence: StockWealthBD · Enterprise DMS · Eskimi DSP · Fairpattern

AI-Enabled Products

I connect document processing, retrieval, RAG, and LLM providers to real workflows—so AI becomes a product capability rather than an isolated demo.

System problems: Private knowledge access, OCR and document understanding, reliable retrieval, provider integration, and human-review workflows.
Evidence: RAG Builder · Fairpattern DMS · Business Setup Automation

WEB

Full-Stack Product Delivery

I stay close to the interface so the architecture becomes a clear, usable product—translating domain complexity into workflows people can trust and operate.

System problems: End-to-end workflow design, frontend integration, product clarity, and turning technical correctness into dependable user experiences.
Evidence: StockWealthBD · Eskimi DSP · Soudia Bus · MetLife EFT

SEC

Secure Integrations

I build the discipline behind systems that move money and sensitive data: secure exchanges, explicit states, traceable handoffs, and integrations that survive operational pressure.

System problems: Banking and wallet integrations, EFT processing, virtual-card security, encrypted requests, and fund-transfer workflows.
Evidence: SSL Wireless · FastPay · IFIC Bank integration · Padma Wallet

Education & certifications

The foundations beneath the practice.

Education

2012 - 2017

B.Sc. in Computer Science & Engineering

University of Chittagong

2009 - 2011

HSC, Science

Chittagong Government City College

2008 - 2009

SSC, Science

Nasirabad Government Boys' High School

Certifications

Web Application Development

BASIS

Cloud Journey with AWS