~25%faster API responses
Performance is a feature
- Practice
- Refactor the service architecture and strip out redundant database queries.
- Result
- Fewer redundant queries and steadier behaviour under load.
Hello, I am
TahfimIbnKhan
>
I design reliable, scalable backend systems — and the interfaces that make them feel effortless.
- Based in
- Paderborn, Germany
- Status
- Werkstudent Candidate
- Available
- From Oct 2026
02Who I Am
I build enterprise HR and recruitment systems with Laravel, Node.js and PostgreSQL, and I’m going deeper on AWS and the Square payments API.
Backend services, REST APIs and payment flows at work — personal projects the rest of the time, where most of my open-source repos come from.
- Current role
- Associate Backend Engineer
- Company
- Monstarlab Bangladesh
- Degree in progress
- MSc Computer Engineering
- University
- Universität Paderborn
- Languages
- English C1 · German (learning)
- Work eligibility
- Up to 20 hrs / week
03How I Build Things
Three principles behind every system I ship.
SEOvisibility restored
Migrate without regressions
- Practice
- Move legacy systems onto Next.js / NestJS, guarding against migration regressions.
- Result
- Search visibility restored after the platform migration.
100%idempotent payments
Correctness in money flows
- Practice
- Build payments with idempotency, authorize / capture, refunds and signed webhooks.
- Result
- Idempotent end-to-end, with every webhook HMAC-verified.
04Enterprise Experience
Where I've shipped real systems.
Associate Backend Engineer
PresentMonstarlab Bangladesh•Oct 2025 — Present
Contributing to 3 concurrent projects across multiple teams under divided allocation, spanning backend and frontend development.
3
concurrent projects
1,000+
active users served
~25%
faster API responses
- Develop backend features for MPeople, an enterprise HR management system built with Laravel and PostgreSQL, serving 1,000+ active users.
- Refactor core service architecture to cut average API response time by ~25% and eliminate redundant database queries, improving stability under load.
- Support RJIT's legacy-to-modern system migration (Next.js / NestJS), resolving migration-related SEO regressions to restore search visibility.
- Build core RJIT features including Hot Jobs, a subscription-based job-posting flow, and a Strapi-based CMS, with supporting UI implementation.
- Build frontend features for MRecruitee using React, TanStack Router, TanStack Query, Zod, React Hook Form, and Zustand.
- Completed hands-on implementation of the Square payment system as part of an internal learning goal, gaining practical experience with payment integration workflows.
LaravelPostgreSQLNestJSNext.jsReactStrapiSquare API
Software Engineering Intern
Monstarlab Bangladesh•Jul 2025 — Sep 2025
Assisted engineering teams on internal Laravel applications, from feature work to debugging and architecture discussions.
- Assisted in developing and maintaining Laravel-based internal applications with PostgreSQL.
- Debugged issues and implemented small feature improvements.
- Collaborated with engineers on system architecture and workflows.
LaravelPostgreSQL
05Selected Projects
Four builds, four different problem spaces.
Production work at Monstarlab. Source is private — the write-ups below describe the parts I owned.
Recruitment
RJIT
Full-stack developmentRestaurant Jobs In Thai
Thailand-based restaurant recruitment platform. Full-stack bug fixes, feature updates, and system improvements, including a legacy-to-modern migration and SEO recovery.
Next.jsNestJSPostgreSQL
Enterprise HR
MPeople
Backend engineeringOffice Management System
Backend modules for attendance, meal booking, expense, and leave management — automating daily HR operations for 1,000+ active users.
LaravelPostgreSQLLaravel SubscriptionOneSignal
Recruitment
MRecruitee
Frontend engineeringRecruitment Management Platform
Frontend features for candidate management and hiring workflows, built with the modern React ecosystem and rigorous form validation.
ReactTanStack RouterTanStack QueryZodReact Hook FormZustand
Payments
Cha er Dokan
Backend engineeringMulti-Merchant Square POS Platform
A NestJS backend built on the Square SDK: idempotent payments, authorize / capture, refunds, gift cards, multi-merchant OAuth, and HMAC-verified webhooks.
SquareNestJSReactPostgreSQL
Open Source
Things I build on my own time.
Personal projects I use to try tools before I trust them at work. Every one is public — read the code.
FreshBasket
E-commerce platform
Storefront and API for an online grocery: OTP-based authentication, Stripe checkout, and generated invoices. Split across a NestJS backend and a separate Next.js frontend.
NestJSNext.jsPostgreSQLStripeInventory API
Inventory management backend
A REST backend for stock and order tracking with authentication, built to practise clean resource modelling and route-level authorisation on a document store.
Node.jsExpressMongoDBDairyDirect
Admin dashboard
A dairy retail admin panel covering product catalogue and order control, written against a plain PHP/MySQL stack without a framework.
PHPJavaScriptMySQLAIUB Synapse
Student resource sharing
A desktop resource-sharing tool for university students — notes, materials and coursework — built on C# over an MSSQL database.
C#MSSQLPDF to Audio
Document narration
Converts uploaded PDF documents into playable audio, handling text extraction and speech synthesis end to end.
Node.jsBootstrap
06Tech Stack
The tools I reach for.
Languages
PHPJavaScriptTypeScript
Backend
LaravelNode.jsNestJSRESTful APIsStrapiSquare API
Frontend
ReactNext.jsTanStack RouterTanStack QueryZustand
Databases
PostgreSQLMySQL
Tools
GitGitHubDocker (basic)AWS (basic)PostmanNPM
07Recognition
A few things I'm proud of.
Emerging Star Award
Recognised for outstanding performance and contribution — within the first year.
Monstarlab Bangladesh
Dean's Award ×3
Awarded three times for outstanding academic performance across the BSc.
AIUB
Merit Scholarship
Up to 50% academic scholarship for academic performance.
AIUB
Beyond the code
- Business case-study competitions at AIUB, and the “ADSPIRE” ad-making competition.
- Monstarlab Hackathon — collaborated with developers to build and present ideas.
Interests
TravelVideographyVideo Editing
08The Journey
From Bangladesh to Germany.
2018 — 2020
Higher Secondary Certificate
Govt. Ashek Mahmud College
GPA 5.00 / 5.00
Sep 2021 — May 2025
BSc in Computer Science & Engineering
American International University-Bangladesh
CGPA 3.81 / 4.00
From Oct 2026Incoming student
MSc Computer Engineering
Universität Paderborn
Germany
Languages
EnglishC1
GermanBeginner · learning
Relocating to Germany for an MSc in Computer Engineering — actively learning German to work and study locally.
09Let's build something together
Open to work
I'm an Associate Backend Engineer and MSc Computer Engineering student in Paderborn — available from October 2026, up to 20 hours a week. If your team works with Laravel, Node.js or NestJS, I'd love to hear from you.