Sinan Saleem

Senior Full Stack Engineer

nexario • Full time

Feb 2026 - Present • 7 mos

• Develop and maintain high-performance full-stack web applications using Java, Spring Boot, React, JavaScript, and modern web technologies. • Design and build scalable RESTful APIs supporting secure authentication, business workflows, and third-party system integrations. • Work on high-volume transactional features, performing complex debugging and performance optimization to improve application reliability and responsiveness. • Optimize SQL Server and PostgreSQL databases through query tuning, indexing strategies, and efficient data-access patterns. • Develop reusable frontend components and responsive user interfaces using React to deliver smooth and intuitive user experiences. • Identify backend bottlenecks and improve API, database, and application performance across critical workflows. • Implement secure user-access flows, authentication-state handling, validation, and integration logic for enterprise applications. • Collaborate with cross-functional and globally distributed teams to analyze requirements and deliver production-ready features. • Participate in Agile/Scrum development processes, including sprint planning, code reviews, debugging, testing, and iterative feature delivery. • Follow clean coding, maintainability, scalability, and software engineering best practices when developing and enhancing enterprise-level systems.

Senior Software Engineed

Developlance • Freelance

Sep 2025 - Feb 2026 • 5 mos

• Delivered end-to-end web application solutions for clients, handling requirements analysis, architecture, development, testing, deployment, and ongoing improvements. • Developed scalable full-stack applications using Java, Spring Boot, React, Angular, TypeScript, JavaScript, and Node.js. • Designed and integrated secure RESTful APIs and third-party services to support complex business workflows and system automation. • Built high-performance backend systems with a strong focus on clean architecture, reusable components, scalability, and maintainable code. • Developed responsive and modern user interfaces optimized for usability, performance, and cross-device compatibility. • Worked with PostgreSQL, MySQL, and SQL Server, including database design, query optimization, indexing, and performance improvements. • Modernized existing and legacy applications by refactoring code, resolving technical debt, and implementing new business features. • Diagnosed and resolved complex frontend, backend, API, and database issues to improve application reliability and performance. • Implemented authentication, authorization, validation, and secure application development practices. • Used Git, Docker, Maven, and CI/CD workflows to streamline development, testing, and deployment processes. • Collaborated directly with clients to understand business requirements, provide technical recommendations, and convert ideas into production-ready software. • Managed multiple development priorities independently while maintaining clear communication, timely delivery, and high-quality engineering standards.

Senior Software Engineer

Devsinc • Full time

Mar 2023 - Sep 2025 • 2 yrs 6 mos

Progressed from Associate to Senior Software Engineer, architecting and delivering high-performance web applications. • Developed and maintained enterprise-level solutions, specializing in real estate platforms, custom CRMs, and recruitment software (including the MapleHR product). • Managed the full development lifecycle using Ruby on Rails, React, Node.js, and GraphQL. • Optimized database performance utilizing PostgreSQL and MySQL. • Focused on test-driven development and seamless third-party system integrations to enhance operational efficiency and user experience