Denis Riabchenko - Full-Stack Engineer & Technical Architect

Full-Stack Engineer & Technical Architect

I design and build production systems — from architecture and API design through AI-powered features and AWS infrastructure.

About Me

Engineering systems that scale. Thinking in architecture, not just features.

I'm a Senior Full-Stack Engineer and Technical Architect with 15+ years of experience building complex, production-grade platforms in fintech, enterprise SaaS, and applied AI.

My work spans the full technical stack — system design and data modeling, TypeScript/React frontends, Node.js and Python backends, LLM-powered product features, and AWS cloud infrastructure. I've led teams of 10+ engineers, owned architecture decisions end-to-end, and delivered systems that handle real business complexity at scale.

I'm precise, direct, and focused on building things that last.

Currently based in: Los Angeles, CA

Upwork Expert Vetted

IEEE Senior Member

15+

Years Experience

50+

Projects completed

24/7

Code Thinking

100%

Business Focus

Skills & Technologies

Languages

TypeScriptJavaScriptPythonPHPSQLHTMLCSS

Frontend

ReactNext.jsVueAngularD3.js

Backend & APIs

Node.jsLaravelFastAPIDjangoRESTGraphQLWebSockets

AI Engineering

LLM integrationRAG pipelinesVector embeddingsAI-powered searchData pipelinesModel-driven workflows

Databases

PostgreSQLMySQLMongoDBDuckDB

Cloud & Infrastructure

AWSDockerCI/CDGitHub Actions

Architecture

System designDistributed systemsEvent-driven patternsAPI contract design

Professional Experience

Feb 2023 - Present

Senior Software Engineer & Technical Lead

Aparavi / Santa Monica, CA

Leading a cross-functional engineering team
Architecting and delivering innovative, high-impact solutions.

Aug 2019 - Feb 2023

Lead Software Engineer

Axi / London

Architected and owned full-stack delivery of business-critical financial trading platforms, balancing high-throughput performance, strict data correctness, and operational safety under regulatory constraints.
Designed system architecture for high-availability services including data models, API contracts, failure recovery strategies, and multi-client delivery (desktop and mobile).
Led AWS-based cloud infrastructure improvements supporting thousands of concurrent users, improving reliability and reducing incident frequency.
Defined API design standards around core business concepts rather than database structures, reducing cross-team coupling and accelerating feature delivery.
Led code reviews, architectural improvement initiatives, and debugging efforts that measurably reduced production incidents.
Mentored engineers and delivered internal training sessions to raise overall engineering maturity across the team.

Sep 2015 - Aug 2019

Lead Software Engineer

PsyQuation / Kyiv (Remote)

Architected a high-frequency financial analytics dashboard from scratch — designing the full data pipeline from ingestion through real-time visualization using React and D3.js.
Designed resilient state management patterns handling partial failures, race conditions, and high-frequency late-arriving updates with strict correctness requirements.
Reduced page load time by 50% through systematic performance profiling and targeted React/D3 rendering optimizations.
Established modern engineering practices and mentored junior developers; contributed to platform maturity leading up to company acquisition.

Dec 2012 - Sep 2015

Software Engineer

Truver / Kharkiv, Ukraine

Designed and developed REST APIs and real-time analytics dashboards for petrochemical market data platforms.
Built scalable backend services and data visualization layers, collaborating with stakeholders to align systems with real business workflows.

Jul 2010 - Dec 2012

Software Engineer

Web-Impress / Kharkiv, Ukraine

Delivered end-to-end web applications from initial design through production release, building foundational experience in backend integration, cross-browser compatibility, and client delivery.