Oscar Solideo Siregar

• Delivered full-stack web solutions for multiple clients, developing modern user-facing interfaces and supporting backend services.
• Built responsive frontend features with TypeScript and JavaScript, ensuring clean component architecture and seamless API integration.
• Designed and implemented backend services to support frontend requirements, maintaining consistent data flow and system reliability.
• Collaborated directly with clients to gather requirements and translate business needs into production-ready technical solutions.
• Applied Clean Architecture principles, testing practices, and structured version control workflows to deliver scalable and maintainable applications.

• Developed and maintained core financial systems for a B2B P2P lending platform, supporting high-volume transactional workflows with strong data accuracy and auditability.
• Designed and implemented disbursement and scheduled payment systems, integrated with multiple Indonesian banks.
• Built end-to-end insurance workflows including registration, premium payments, claims, and lender repayment integration.
• Applied Clean Architecture and maintained ~90% unit test coverage.
• Developed reporting and data export features for finance team monitoring.

• Developed and maintained backend systems for various client projects, focusing on scalability, performance, and reliability.
• Designed and implemented RESTful APIs to support web applications and backend services.
• Collaborated with frontend and cross-functional teams to ensure smooth integration and system consistency.
• Handled database design and optimization to improve query performance and data integrity.
• Applied best practices such as Clean Architecture and modular design to maintain code quality and scalability.
• Built and integrated third-party services to support business requirements and automation workflows.
• Delivered reliable backend solutions across multiple domains, supporting real-world applications.

• Delivered fintech and enterprise web applications for PT Telkom Indonesia, improving system efficiency and reliability.
• Designed and developed API-driven backend services using Golang and Node.js (TypeScript) to support CMS and user-facing applications.
• Built a CMS platform from scratch using KeystoneJS v6, enabling structured and scalable content management.
• Improved application performance through Redis caching, significantly reducing content load time.
• Implemented secure authentication systems including social login and LDAP integration.
• Designed asynchronous processing workflows using RabbitMQ for complex survey logic and large-scale data processing.
• Applied Clean Architecture principles and TDD practices, achieving ~90% unit test coverage.
• Enhanced system scalability and maintainability, ensuring the applications could handle increasing traffic and complex business requirements.
• Mentored junior developers and promoted best practices in code quality, testing, and architecture across the team.

Focused on Control Systems in manufacturing environments, studying system stability, feedback control, and automation processes. Developed strong analytical thinking and structured problem-solving skills applicable to complex engineering systems.

Research on adapting Human Machine Interface (HMI) systems for real-time monitoring and control of water quality in aquaculture environments. This work involved sensor-based system integration, feedback control loops, and data visualization — reinforcing my foundation in system design, automation, and analytical problem-solving that I continue to apply in building reliable software systems.

Published research on designing a fuzzy logic controller to optimize crude oil dilution processes in palm oil mills. The work deepened my understanding of control theory, system stability, and structured engineering design — foundations that directly translate into how I approach scalability, reliability, and precision when building software systems today.