Case Study 01
Scaling FinTech Gateways: Why We Chose CQRS over Standard CRUD
A technical breakdown of resolving database bottlenecks in a high-volume payment gateway, reducing dashboard load times by 83%.
Senior Full-Stack Engineer
Ubaid ur Rehman
Specializing in high-volume FinTech ecosystems, complex ERPs, and legacy system modernization.
Full-Stack Software Engineer with 5+ years of experience engineering scalable APIs and dynamic user interfaces using .NET, React, and React Native. Expert in modernizing legacy enterprise systems, implementing Clean Architecture, and optimizing database performance via CQRS.
Technical Arsenal
Backend Architecture
C#.NET 6/8ASP.NET Core MVCWeb APINode.jsClean ArchitectureRESTful APISOLIDDDD
Frontend & Mobile
ReactReact NativeJavaScript/TypeScriptHTML5/CSS3Material UIBootstrapWPFWinForms
Databases & Data Modeling
PostgreSQLSQL ServerOracleMongoDBRocket UniVerseEntity Framework CoreDapperRedis
Cloud, DevOps & Messaging
Microsoft AzureDockerJenkinsRabbitMQCQRSCI/CD Pipelines
Testing & Version Control
JestNUnitSeleniumPlaywrightSpecFlowGit/GitHubAzure DevOpsJira
Proof of Work
Case Study 02
Handling API Idempotency in .NET 8
Designing a bulletproof idempotency handler using Redis to prevent duplicate transactions in distributed banking systems.
Professional
Journey
I am a Senior Full-Stack Engineer with over 5 years of experience building and scaling enterprise-grade applications. My expertise lies in the Microsoft .NET ecosystem (C#, .NET 6/8, Web API), React, and React Native. I specialize in solving hard architectural problems in highly regulated spaces—like banking, FinTech payment gateways, and pharmaceutical manufacturing. Whether it's implementing CQRS to drop dashboard load times from 60 seconds to under 10 seconds, or designing fault-tolerant message brokers with RabbitMQ and Redis, my focus is always on security, scalability, and measurable business impact.
FullStack Software Developer
May 2025 – Present- ▸Architected and optimized backend CRM/ERP solutions, utilizing SOLID principles and DDD to build modular RESTful APIs (.NET 6, PostgreSQL, RabbitMQ) that integrate seamlessly with legacy Rocket UniVerse databases.
- ▸Developed dynamic client-side interfaces and cross-platform mobile components using React and React Native to fulfill end-to-end feature requirements for enterprise dealership solutions.
- ▸Contributed heavily to architectural decisions and team-wide technical documentation by authoring comprehensive SOPs and Technical Specifications for the Accounting Module.
- ▸Implemented rigorous testing strategies and established production reliability for mission-critical systems, utilizing Jenkins CI/CD pipelines and SonarQube.
.NET 6ReactReact NativePostgreSQLRabbitMQDDD
Software Developer
Jan 2025 – Apr 2025- ▸Designed and implemented microservices-based server-side solutions for a leading FinTech gateway using .NET 6 & 8, engineering high-performance caching and messaging layers with Redis and RabbitMQ.
- ▸Optimized database structures by implementing CQRS, dedicated read databases, and normalized transaction tables, reducing core dashboard load times from over 60 seconds to under 10 seconds.
- ▸Integrated third-party systems via robust APIs for secure account registration and financial transactions.
.NET 8MicroservicesRedisCQRS
Software Engineer
Jul 2024 – Dec 2024- ▸Developed complex features and high-performance desktop user interfaces utilizing Windows Presentation Foundation (WPF) for Trafix OMS, ensuring data integrity for a globally redundant trading platform.
- ▸Refactored existing code to migrate application from .NET Framework 4.8 to .NET 8, resolving breaking changes to guarantee core stability for globally active clients.
- ▸Executed rigorous System Integration Testing (SIT) and Unit Testing to ensure zero-downtime software releases.
WPF.NET 8.NET Framework
Software Engineer
Aug 2023 – Jun 2024- ▸Engineered secure backend features and complex stored procedures for digital banking platforms, ensuring seamless collaboration with stakeholders.
- ▸Executed a massive customer data migration, ensuring 100% data integrity and security with zero downtime.
- ▸Developed critical backend services for a Bank CRM upgrade, including Windows services for automated Eform updates.
C#SQL ServerDigital Banking
Technical Consultant
Nov 2021 – Jul 2023- ▸Engineered C#-based logic and complex data reports for an MES-based ERP tailored for highly regulated pharmaceutical manufacturing.
- ▸Collaborated seamlessly with distributed international client teams to deliver production deployments and technical training.
C#ERPMES
Software Developer
Jul 2020 – Oct 2021Sentore-Tech
- ▸Built and maintained backend services and batch processing jobs that handled 10,000+ concurrent API validations.
- ▸Developed inventory and POS features using .NET Framework and SQL Server.
- ▸Implemented web and desktop interfaces with ASP.NET MVC and WinForms for day-to-day operations.
ASP.NET MVCWinFormsBatch Processing
Visiting Faculty (Software Engineering)
Sep 2022 – Feb 2026- ▸Facilitated technical interviews and deep-dive code evaluations for software engineering cohorts.
- ▸Instructed core technical courses including Software Architecture and Web Engineering, assessing fundamental engineering concepts, data modeling, and architectural patterns.
MentorshipSoftware Architecture