# Aleksandr Holub

> Senior Software Engineer at Microsoft | Identity & Security | Large-scale AuthN/AuthZ Systems

Location: Redmond, Washington, United States
Profile: https://flows.cv/aleksandrholub

I build authentication and authorization platforms that handle tens of millions of requests per second. My expertise is in distributed systems, security protocols (OAuth2, OIDC), and observability at scale. Currently at Microsoft, driving identity security for thousands of services. I enjoy designing resilient systems that balance performance, security, and developer experience.

## Work Experience
### Senior Software Engineer - Identity & Network Access Division @ Microsoft
Jan 2024 – Present | Redmond, Washington, United States
- Developed and led the rollout of a security solution that prevents unauthorized trust between US Government and public cloud environments by ensuring cryptographic keys are isolated for each cloud. This initiative significantly strengthened data protection for government workloads, reduced risk of cross-cloud token misuse, and set a new standard for secure cloud authentication at Microsoft.
- Directed multi-team efforts to design and implement end-to-end observability for large-scale identity and compliance pipelines, including real-time monitoring, alerting, and telemetry for big data flows.
- Led a cross-functional team to design and implement a multi-tenant architecture for a global identity platform, enabling secure, isolated configurations for thousands of enterprise applications.
- Owned high-severity incident response, coordinating engineers and partner teams to restore service quickly and implement long-term preventive measures.

### Senior Software Engineer @ Goodfynd
Jan 2023 – Jan 2024 | Texas, United States
As a Full Stack Senior Software Engineer at Goodfynd, I spearheaded the optimization of application stability and development velocity by solving architectural challenges.
My responsibilities included redesigning the software architecture by integrating advanced architectural principles, which significantly improved system stability and streamlined the development process.
I also optimized API and database interactions, enhancing server response times and overall system efficiency, while fostering a collaborative and efficient development environment.

- Integrated key architectural principles and styles, doubling code efficiency and accelerating the development cycle by 100%, which streamlined project delivery timelines.
- Enhanced database query performance by 300%, resulting in a twofold increase in database interaction speed and significantly improving overall system responsiveness.
- Conducted over 10 knowledge-sharing sessions, educating peers on advanced software development techniques and best practices.

### Senior Software Engineer @ Namecheap, Inc
Jan 2020 – Jan 2023 | Texas, United States
As a Full Stack Senior Software Engineer at Namecheap, the second largest domain name registrar globally, I specialized in distributed systems architecture.
My responsibilities encompassed designing and developing microservices to introduce new functionalities, crafting robust APIs, and managing database operations.
I also contributed to frontend development and actively participated in the production deployment process, ensuring seamless integration and performance across all services.

- Developed over 20 microservices and micro-frontends to establish highly scalable web services, driving $200M of revenue every year.
- Implemented and designed domain business logic, leading to a significant 23% increase in global revenue.
- Responsible for system design of new features and selection of technologies used in new services.
- Coordinated with cross-functional teams to align priorities and collaboratively achieve project goals.

### Senior Software Engineer @ Dedicated Lab
Jan 2019 – Jan 2020 | Kharkiv, Ukraine
As a Full Stack Senior Software Engineer at Dedicated Lab, I focused on modernizing the software architecture by breaking down a monolithic application into a microservices-based architecture.
My responsibilities involved integrating Domain-Driven Design (DDD) paradigms and implementing the Command Query Responsibility Segregation (CQRS) architectural style to enhance scalability and maintainability.
Additionally, I led the development of various subsystems, ensuring robust performance and seamless functionality across the platform.

- Integrated asynchronous communication between services, enhancing inter-service data flow and responsiveness.
- Refactored a monolithic application into more than 10 microservices, significantly improving system maintainability.
- Implemented distributed transactions across microservices, bolstering application robustness and ensuring consistent data integrity.
- Mentored two team members, fostering their professional growth and enhancing team capabilities.

### Software Engineer @ Tideworks Technology
Jan 2014 – Jan 2019 | Ukraine
Worked on dynamically controlling container handling equipment in a terminal. I integrated new functionality into a tightly coupled system, performed extensive refactoring, and wrote numerous procedures in Oracle.
Subsequently, I transitioned to a project focused on gaining experience in distributed systems. This involved developing microservices using Java and React, applying Domain-Driven Design (DDD) principles, and utilizing Kafka for messaging. Although unfamiliar with these technologies initially, I dedicated myself to learning and studying extensively, making it a highly engaging and enriching experience.

- Developed 3 cutting-edge applications for managing automated cranes at container terminals.
- Reduced manual error by 40% through IoT integration.
- Developed and refactored 50+ Oracle procedures, enhancing database performance by 50%, leading to a reduction in system downtime.

### Software Developer @ LULU Software (an Avanquest company)
Jan 2014 – Jan 2014
Ad-aware WebComponion
Add new big module (SearchProtect) to existing project. SearchProtect controls browser settings.

•	PERSONAL RESPONSIBILITIES:
Frontend and Backend development
Unit tests

•	TOOLS AND TECHNOLOGIES:
C# .Net, WPF (MVVM), Resharper7, TFS, SVN

### Software Engineer @ SMISS
Jan 2012 – Jan 2013
Dante (HP Quality Center)
Update of existing modules to new level of functionality and UI.
•	PERSONAL RESPONSIBILITIES:
	Frontend and Backend new features development
	Unit tests
•	TOOLS AND TECHNOLOGIES:
	C# .Net, Win Forms, TFS


## Education
### Junior Specialist’s degree in Computer-Aided Management Systems Software Engineer
Kharkov Patent Computer College


## Contact & Social
- LinkedIn: https://linkedin.com/in/alex-holub-ua
- Website: https://www.oleksandrholub.com
- Website: https://www.sharelink.dev
- GitHub: https://github.com/alexholub113

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Source: https://flows.cv/aleksandrholub
JSON Resume: https://flows.cv/aleksandrholub/resume.json
Last updated: 2026-03-22