Sergio Oberemchuk
@sergiooberemchuk
I build high-scale backend, trading, payments, and deployment platforms.
SpainWhat I'm looking for
I've built production systems for The TMRW Foundation, CEX.IO, UBS, and UkrSibbank, with more than 20 years in backend engineering and architecture. My work spans financial systems, crypto-exchange trading engines, payments, identity, and cloud platforms where correctness and reliability are non-negotiable.
At The TMRW Foundation, I replaced legacy Java services with typed Node.js services and delivered more than 23x performance improvement through architectural redesign. I also took an authenticated deployment platform from proof of concept to production, owning its release path and cutting 60 of its first 61 production releases.
I work deeply with PostgreSQL, distributed messaging, cloud infrastructure, and secure delivery pipelines. Earlier, I migrated 10TB from MongoDB to PostgreSQL against a live product, built low-latency trading systems at CEX.IO, and delivered FX settlement processing for UBS.
Experience
Work history, roles, and key accomplishments
Senior Backend Engineer
The TMRW Foundation
Dec 2024 - Present (1 year 9 months)
Replaced a legacy Java backend with typed Node.js services and took a deployment-platform proof of concept to production. Achieved over 23x performance improvement and authored or reviewed 74% of pull requests.
Software Engineer / Architect / Consultant / Researcher
Self Employed
Dec 2023 - Dec 2024 (1 year)
Provided consulting services in software architecture, cloud computing, and cybersecurity. Conducted hands-on R&D across GCP services and IoT with home-automation prototypes.
Collaborated with cross-functional teams to design, implement and deploy solutions. Led migration from PostgreSQL 9 to PostgreSQL 15 and optimized ClickHouse for performance.
Developed new features for web/mobile product and integrated with external services. Streamlined iOS/Android builds with Fastlane and designed secure REST/WS APIs.
Developed a real-time distributed data-processing system for UBS within the FX Strategic Renewal program. Integrated new features into the FX settlement platform (SWIFT messages processing).
Senior Software Developer
UkrSibbank / BNP Paribas Group
Mar 2008 - Apr 2010 (2 years 1 month)
Designed, developed and tested modules for a consumer-finance application built from zero for high availability. Implemented key architectural concepts including flow navigation and database schema design.
Senior Software Developer / Architect
Incom
Feb 2006 - Mar 2008 (2 years 1 month)
Developed and integrated Selfcare system for Kyivstar mobile operator. Designed and integrated USSD and SMS services (JAIN SLEE solution).
Education
Degrees, certifications, and relevant coursework
Kyiv Business Institute of NTUU “KPI”
Specialist, Organizational Management
2002 - 2004
Specialist degree in Organizational Management from the Kyiv Business Institute of NTUU “KPI”.
National Technical University of Ukraine “KPI”
Specialist, Radio Engineering
1998 - 2004
Specialist degree in Radio Engineering (Master’s equivalent) from the National Technical University of Ukraine “KPI”.
Tech stack
Software and tools used professionally
OpenAPI
Selenium
GitLab
Kubernetes
Helm
GitHub Actions
PostgreSQL
MongoDB
Oracle
Node.js
Spring Boot
Spring
NestJS
Spring Framework
Redis
Terraform
Gradle
Mocha
React
GWT
Webpack
JavaScript
Java
Lua
Log4j
RabbitMQ
MQTT
fastlane
Grafana
Prometheus
Sequelize
Hibernate
Stripe
GraphQL
Prisma
TypeScript
Keycloak
OAuth2
Git
Docker
Clickhouse
React Router
Cloudflare Workers
Playwright
tRPC
OpenTofu
Cloudflare D1
Cloudflare R2
k6
Claude Code
Pino
Availability
Location
SpainAuthorized to work in
Salary expectations
Job categories
Skills
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