Oleksiy Pylypenko

Principal Software Engineer · Platform & API Architect

I design and build software platforms and APIs, with more than 20 years of experience across banking, enterprise software, and open source. My work combines architecture, hands-on engineering, and technical leadership: setting direction, delivering systems, and helping teams operate them in production.

Experience

Connectivity / API Architect — Kyriba

• Led the move to API-first development, combining implementation, architecture standards, and adoption across teams. The work included 1,085 pull requests, 234 API contracts, and 89 RFC-style REST guidelines.
• Led the replacement of an in-house API gateway with Gravitee, from CTPO approval and architecture-board reviews through delivery. Built 43K lines of integration code, including Java-based Kubernetes operators.
• Developed and delivered training in Gravitee APIM and advanced Kubernetes: 20 sessions and 12 hands-on exercises over 10 days.

Technologies: Java, Spring Boot, OpenAPI, Gravitee, Kubernetes.

Platform Engineering Tech Lead — UBS

• Led engineering of the cloud-based microservices platform within a system serving 1.8 million users, addressing limitations of the on-premises environment.
• Built platform components in Java, GitOps delivery pipelines, Helm charts, and TypeScript/React dashboards.
• Prepared solution architecture and production-transition documentation, and trained platform and application teams.
• Diagnosed and resolved production issues across networking, certificates, Kubernetes, and service meshes, using tools including tcpdump and Splunk.

Technologies: Java, Kubernetes, Helm, GitOps, TypeScript, React, HTTP/TCP, X.509.

Selected projects

• MockK — Created the Kotlin mocking library, writing approximately 40K lines of its implementation. It has 5.7K+ GitHub stars, reached the Adopt ring on the ThoughtWorks Technology Radar, and is referenced in the official Android testing documentation.
• Vibe Coding — Personal projects built with AI, documenting the products, architecture decisions, and supporting homelab.
• Effective Retro — Built a retrospective board at a bank hackathon in 2018. It grew into a bank-wide tool and remained in use after I left; the organization later rewrote it while retaining the design.

Engineering approach

I use API specifications to make interfaces explicit and consistent. I focus on developer experience, operational reliability, and the tooling that helps teams deliver and maintain their systems. My architecture work stays close to implementation, security, testing, and production support.

Core skills

• Architecture: API design, platform engineering, cloud platforms, production readiness.
• Development: Java, Kotlin, Spring Boot, TypeScript, React.
• Infrastructure: Kubernetes, GitOps, Helm, API gateways, service meshes.
• Technical leadership: Architecture reviews, engineering standards, documentation, workshops, and hands-on training.

Writing

• Software Architecture in the AI & Cloud Era — A free online book with 15 chapters on the path to platform architecture.
• How Apache Cassandra works — A detailed explanation of Cassandra internals, published in 2012, with 267K views.
• Simple Ethics · School Olympiads · YouTube Summaries

Beyond work

ICPC winner. Interested in teaching, experimental software projects, VR, and gaming.

Links

GitHub · LinkedIn · MockK · The Book