Oleksandr Chaplyga

Oleksandr Chaplyga

Tech Lead · Senior Backend Engineer (Node.js / NestJS)

FinTech · RegTech · High-load SaaS · Marketplaces

  • 13+ years in software
  • EU Blue Card · Spain
  • Open to Lead / Head roles
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Profile

Engineering leader with 13+ years of building products from the first line of code to stable, high-traffic production. I specialise in backend architecture with Node.js and NestJS — designing scalable, secure systems for digital wallets, payments, regulatory compliance and high-load SaaS.

As a hands-on Tech Lead, I combine architectural ownership with people leadership: setting engineering standards, mentoring developers, reducing delivery risk and translating business goals into clear technical plans together with Product, QA, UI/UX and PMs. I am comfortable owning production — infrastructure, databases, monitoring and incident response — not just the code.

  • 13+years building production software
  • 5products architected from scratch
  • FinTechwallets, balances & payment flows
  • ISO 27001audits & certification hands-on

Experience

Team Lead / Tech Lead

Jan 2024 – Present

Digital Wallet & E-Commerce Marketplace · Europe

  • Lead end-to-end development of a high-load digital wallet built from scratch on Node.js and NestJS, processing heavy traffic and complex financial transactions.
  • Own the full product lifecycle — from initial architecture and technical roadmap to production launch and long-term support.
  • Architected a broad set of third-party integrations (compliance, KYC and retention tools) while keeping strict data-security requirements.
  • Set up high-performance production environments with monitoring and alerting to ensure reliability and fast incident response.
  • Lead and mentor the engineering team: code reviews, engineering standards, sprint planning and alignment with business stakeholders.

Stack: Node.js, NestJS, TypeScript, microservices, CI/CD, cloud infrastructure, monitoring

Senior Software Engineer

Jan 2021 – Jan 2024

All-in-One RegTech Engine for Business · Limassol, Cyprus

  • Analysed regulatory technical requirements and led integration of mandatory external APIs and compliance gateways.
  • Engineered core modules in line with ISO 27001, data-privacy regulations and financial certification frameworks.
  • Took part directly in regulatory audits and certification — delivering technical documentation, audit logs and security controls that secured platform approval.

Stack: Node.js, TypeScript, distributed systems, MySQL, Redis, Docker, AWS, security APIs

Senior Software Engineer

Jun 2019 – Jan 2021

SaaS Startup · Kyiv, Ukraine

  • Architected and scaled the core engine of a high-load SaaS platform from scratch to production.
  • Built key financial modules: real-time user balance processing and integrations with payment gateways and marketing tools.
  • Designed background workers and data-streaming pipelines for heavy asynchronous workloads.
  • Resolved critical database bottlenecks, optimised the architecture and took an active role in incident management to keep the platform fast and highly available.

Stack: Node.js, MySQL, Redis, RabbitMQ

Senior Software Engineer

Oct 2018 – Jun 2019

United Travel Ticket · Kyiv, Ukraine

  • Architected a transport ticket aggregator from scratch, unifying diverse transport providers into a single global network.
  • Engineered multi-modal routing algorithms that plan complex journeys and return fast results, optimising for price, travel time and layovers.
  • Owned the full lifecycle from system design to production deployment.

Senior Full-Stack Developer

Jan 2018 – Oct 2018

Full-Stack Developer

Nov 2013 – Jan 2018

SPECTR.Media · Kyiv, Ukraine · 5 years

  • Delivered full-stack e-commerce solutions end to end: server setup, backend development and secure integrations with payment gateways and logistics providers.
  • Built custom front-end applications with a focus on pixel-perfect markup, performance and technical SEO that drove organic growth.
  • Grew from developer to senior engineer, taking ownership of architecture and deployment.

Core competencies

  • Software architecture & system design
  • Node.js & NestJS at scale
  • High-load & distributed systems
  • Financial transactions & integrations
  • Technical leadership & mentoring
  • Code review & engineering standards
  • CI/CD, DevOps & automation
  • Production support & incident response
  • Security & regulatory compliance
  • Agile / Scrum delivery