Alexander Zagaynov

Lead Software Engineer with 25+ years of experience modernizing production systems across enterprise, fintech, cloud, and infrastructure environments, with a focus on legacy transformation, reliability, CI/CD, and security hardening.

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Core Skills

Languages
Ruby, Python, Java, Kotlin, JavaScript, TypeScript, SQL, Bash
Frameworks
Ruby on Rails, Spring Boot, Vue.js
Cloud & DevOps
Azure, AWS, GCP, Kubernetes, Docker, Terraform, Ansible, Azure DevOps, Jenkins, GitHub Actions
Data & Messaging
PostgreSQL, MySQL, MongoDB, Redis, Kafka, RabbitMQ, REST, GraphQL, SOAP/WSDL
Security & Quality
Microsoft Entra ID, TLS/PKI, internal CA, WAF, SonarQube, Veracode

Certifications

Microsoft Certified: DevOps Engineer Expert, Azure Administrator Associate, and Azure AI Fundamentals; AWS Certified Solutions Architect - Associate; Red Hat Certified Engineer, Red Hat Certified System Administrator, and Red Hat Certified Specialist in Ansible Automation.

Experience

Lead Software Engineer · AT&T

Oct 2023 - Present

  • Hands-on modernization and support of 2 large enterprise applications (Java/Kotlin, Spring Boot, Vue.js, TypeScript) plus supporting internal services.
  • Migrated major applications from Spring Boot 2 to 4 and Vue 2 to 3, and modernized 3 Python legacy services, reducing technical debt and improving maintainability.
  • Integrated Microsoft Entra ID, strengthened TLS/PKI, internal CA, and WAF-related security, integrated SonarQube and Veracode, and designed Azure DevOps CI/CD pipelines.

Lead Software Engineer · EPAM Systems

Apr 2020 - May 2023

  • Worked with a European banking platform vendor and two live banks in high-load, regulated environments across engineering, SRE, integration, and production support.
  • Resolved critical production incidents across dozens of Ruby- and Java-based microservices, including one approximately 100x speedup; investigated unfamiliar codebases in Java, Python, Go, Swift, and Ruby.
  • Delivered PSD2 integrations across REST/JSON, SOAP/WSDL, and messaging; modernized Rails services and CI/CD pipelines; supported release readiness, RCA, and mentoring.

Software Engineer · Red Hat

Dec 2016 - Jan 2020

  • Contributed to OpenShift QE and ManageIQ hybrid cloud platform development.
  • Built test frameworks, led AWS STS integration, upgraded SDKs, and contributed to AWS, Azure, and GCP cloud integrations.
  • Worked as an active open-source contributor across code, reviews, and upstream collaboration.

Full-Stack Engineer · Mamapedia

2015 - 2016

  • Modernized a legacy Rails 2.x platform on Ruby 1.8.7, improving rendering performance by about 2x, and added AJAX-powered instant search with improved Apache Solr integration.
  • Improved security with encrypted passwords and tokenized password resets, rebuilt the personalized daily email digest system, and automated AWS deployments with Capistrano, Salt, and Terraform.

ERP & Infrastructure Consultant · Independent and client work

1998 - 2014

  • Delivered ERP, WMS, CRM, and enterprise infrastructure solutions across multiple industries, including custom business platforms and data-center modernization projects.

Professional Development

IT Project Management, I Heart Stats (Notre Dame, edX), Entrepreneurship 101 (edX).