Real Estate Operations Platform
Modernizing a decades-old real estate platform: 50M+ records from ASP.NET/MSSQL to NestJS
Open to full-time and part-time remote roles
Sifat RabbiStaff Software Engineer · Remote, Full-Time
I led a migration of a legacy ASP.NET/MSSQL system with 50M+ records to NestJS, PostgreSQL, and AWS, cutting a core query from 60 seconds to 500ms. That is the kind of ownership I bring as a Staff Software Engineer with 7+ years of production work across healthcare and fintech.
I work remotely and full-time as a Toptal-vetted engineer (top 3%), owning architecture, development, and deployment end to end for US-based clients. Core stack: Next.js, NestJS, TypeScript, PostgreSQL, AWS, and Prisma, plus FastAPI services for LLM-powered and retrieval-augmented generation features. I hold a Computer Engineering degree from AUST, where I now teach as an adjunct lecturer.
- Years
- 7
- Roles
- 11
- Projects
- 4
Work
Selected work
Production systems with architecture, constraints, and measured outcomes.
4 projects · 1 live
Career
Experience
7 years across 11 roles.
Dec 2025 – Present
CurrentSenior Software Engineer
- Architected and delivered the entire platform from scratch, covering front end (Next.js), back end (Payload CMS and API routes), PostgreSQL database design, third-party integrations, and production deployment on Netlify.
- Designed a highly normalized yet query-efficient PostgreSQL schema tailored to mental health and autism care data. Applied caching at key layers to minimize redundant queries and ensure fast response times across search and listing flows.
Aug 2025 – May 2026
Full Stack Developer
Clerk Data LLC (Via Toptal)·9m
- Migrated a legacy ASP1/MS SQL application to a modern NestJS/React stack, eliminating technical debt from a Windows 95-based system and establishing a scalable, cloud-native architecture on AWS.
- Reduced page load times by 98%, optimizing queries on 50+ million record tables to execute in under 500ms compared to previous 60+ second wait times through database restructuring and strategic caching.
Jun 2024 – Jan 2025
Full-stack Engineer | Health Benefits Product
- Improved scalability to meet client's requirements.
- Made the application more secure as it contains bank account and transaction information.
Jan 2023 – Apr 2023
Full-stack Engineer
A Toptal Client·3m
- Developed multiple apps using Next.js with serverless functions.
- Used MUI for the front end and made the website responsive for mobile view.
Skills
How I usually build
The stack I reach for on product work, from the UI down to the data layer.
- SOC 26y
- Retrieval Augmented Generation (RAG)2y
- AI Integration3y
- TypeScript5y
- React6y
- Node.js6y
- Amazon Web Services (AWS)6y
- Next.js6y
- Algorithms
- Data Structures
- MySQL
- SQL
- CSS
- JavaScript
- Agile
- Amazon S3 (AWS S3)
- API Architecture
- API Development
- API Integration
- Authentication
- AWS SDK
- Bootstrap
- Caching
- Cloud
Writing
Recent writing
First-hand notes from production work, interviews, and tools I actually used.
Testimonials
What people say
From clients and people I've worked with.
TO
Toptal
Staff Software Engineer at Toptal (remote)
“5000+ hours across long-running remote roles, 8 client teams, 100% client satisfaction.”
Toptal
UP
Upwork Client
Client on Upwork
“Outstanding Web Developer – Expert in TypeScript, AWS, HTML, and CSS. Working with Sifat has been an exceptional experience from start to finish. His deep expertise in modern front-end technologies, especially TypeScript, HTML, and CSS, combined with a strong command of AWS services, made a significant impact on the success of our project.”
Upwork
UP
Upwork Client
Client on Upwork
“Sifat has been delivering excellent value since the beginning. He shared his experience and suggested how we could work together with best standards making it easy all along the project. He delivered an initial version extremely fast so we could provide feedback quick and after some iterations we achieved a solid end version. I really liked his communication skills and that he offered an excellent support.”
Upwork
YS
Yemin Sajid
Co-Founder, CEO @ Greentech Apps Foundation
“Sifat is an avid problem solver and enthusiastic about writing clean codes. He is someone you can rely on to finish any tasks on his own. He also cares about his team members and helping them grow. He shared the same value as our organization during his time with us. He not only does the work assigned, but also shows proactiveness in suggesting better alternatives. Working with him was a great pleasure, and his contributions were pivotal for our organization.”
MN
Md Ashif Al Nowajesh
Senior AI Solution Architect
“I've had the pleasure of working with many professionals in our line of work, but Sifat is someone whom I will always remember fondly. He is a great engineer and an outstanding team player with rich experience in software development and is always willing to lend a hand to anyone who needs it. Any company would be lucky to have Sifat on their payroll”
RA
Rumman Ali
MSc Computer Science @ University of Windsor
“I am delighted to provide this recommendation for Sifat, my exceptional classmate and friend. Throughout our academic journey, I had the privilege of witnessing his remarkable abilities and unwavering dedication. Sifat's problem-solving skills are truly exceptional... He possesses a unique ability to break down problems into manageable components and arrive at innovative solutions.”
Contact
Let's work together
If you're hiring for a remote Staff or Principal role, or building something in healthcare, fintech, or AI, email me and we can talk it through.
Open to full-time and part-time remote roles
Also on Toptal. Email is the best way to start a conversation.