Sajjad H.

Greetings: ✅ Top Rated Plus (Top 3% on Upwork) ✅ 9,000+ Production Hours Logged ✅ 100% Job Success Score ✅ 8+ Years of Enterprise Architecture & Domain Data Engineering Experience Are slow database queries, complex data pipelines, or legacy Java and .NET systems holding back your application's performance? I am a Senior Software Engineer specializing in Java backend architecture, .NET Core microservices, and enterprise Data Management. Having delivered over 9,000 hours of mission-critical development across major IT firms and global enterprise clients, I transform complex backend codebases into fast, secure, and maintainable systems. Core Technical Stack: ✅ Modern Java & Microservices: Java (8 to 21), Spring Boot, Spring Cloud, Hibernate / JPA, RESTful APIs, OpenAPI/Swagger, JUnit/Mockito, Maven. ✅ .NET & API Engineering: C# .NET Core, ASP.NET Web API, SOAP Services, JWT/RBAC Security, Microservices Architecture. ✅ Data Management & Database Tuning: PostgreSQL, MySQL, Oracle, NoSQL (MongoDB, DynamoDB), custom schema indexing, execution plan tuning, and query diagnostics. ✅ Complex Data & Geoscience Connectors: End-to-end processing of heavy 3D Grid data, custom interoperability connectors across SLB Petrel, Studio, and Halliburton DSG platforms, domain standards (e.g., RESQML V2), and C++/Java native integrations via Apache Thrift. ✅ Legacy System Modernization: Migration and maintenance of legacy enterprise systems (EJB, Servlets, JSF, Struts, Swing, JavaFX, JDBC). ✅ Full-Stack & DevOps: Angular, React, PrimeFaces, Tailwind CSS, Docker, Git workflows, and remote Linux deployments. Featured Applications & Projects Built ✅ Inter-Platform E&P Data Connectors: Architected secure data integration pipelines to transfer heavy 3D Grid models, custom entities, and spatial datasets seamlessly between SLB Petrel, Studio, and Halliburton DSG ecosystems, introducing custom security, entity validation, and data mapping. ✅ Innovation Management Platform (Skild Inc.): Designed and scaled backend event-processing services, user registration workflows, and high-concurrency APIs for large-scale production events. ✅ Shipment & Tracking Management System: Architected real-time tracking microservices, logistics databases, and RESTful integration endpoints for global shipment management. ✅ EDOC Information Management System: Built a secure, high-throughput document tracking and enterprise records management platform with role-based access control. ✅ Telecom Tower Management System: Engineered backend infrastructure for monitoring tower assets, spatial grid data, operational status, and maintenance workflows. ✅ High-Throughput Data Parsers: Developed standalone processing engines for binary formats, RESQML files, and complex spatial grid structures. Whether you need a full codebase refactor, complex data connectors, database query optimization, or an end-to-end Spring Boot service built from scratch, I can help. Click "Invite to Job" on the right side of this page to discuss your project requirements!