Experience

Every role with what I owned, not just the title. Skills carry years and the projects that prove them.

Work history

2025 — now

Founder & Principal Engineer — Flexipy OÜ

OwnedSolution architecture on every project — system design, data modeling, integrations and scaling — while staying hands-on for core and high-risk components. Technical discovery and pre-sales, engineering standards, hiring and mentoring a senior-only remote team.

Dev13 Systems — architected and built an AI-native business OS end to end: 8 modules and 25+ Claude-powered specialist agents in production on a human-approval workflow, with MCP servers exposing platform tools to the agents
Built the shared retrieval and evaluation layer behind every AI project — hybrid search over pgvector and Qdrant with reranking, Langfuse and LangSmith tracing, LLM-as-judge regression tests on golden datasets, per-tenant token and cost tracking
Leon & Vera — AI lead-generation SaaS for European real-estate brokers over the WhatsApp Business API; live in 6 markets with subscription billing, GDPR and EU AI Act compliance
AI voice-agent SaaS on Azure — realtime telephony over Twilio Media Streams driving Azure OpenAI speech-to-speech inside a strict latency budget; the client returned for a second, larger phase

Python Django FastAPI Celery OpenAI / Azure OpenAI Claude LangChain LangGraph MCP servers PostgreSQL pgvector Qdrant Redis Docker AWS Azure React

2024 — 2025

Fractional CTO & Principal Engineer — OnFire Messenger

OwnedTechnology strategy across a multi-domain platform — messaging, learning, marketplace and payments — plus the core backend services and the infrastructure they run on. Product direction, backlog and release planning with the founders.

Designed the AI agent layer — assistant workflows, LLM tool calling across every platform module and task automation, driven by a single-button assistant
Built real-time messaging across text, voice and video
Delivered wallet and payments — token balances, Mastercard-powered card issuing, crypto-to-fiat conversion and settlement flows
Advised the founders on architecture, build-vs-buy, vendor selection and risk

Python Django FastAPI Celery OpenAI / Azure OpenAI PostgreSQL Redis Docker AWS

2024 — 2024

Lead Python Software Engineer — Symphony Solutions

OwnedFeatures end to end on an enterprise whistleblowing platform used by Fortune 100 companies and government agencies — design, implementation, tests and deployment — plus architecture decisions across platform services.

Ran enterprise onboarding implementations for large customers
Mentored engineers, ran code reviews, owned team performance and development plans
Reported status, risks and decisions to internal and client-side stakeholders

Python Django PostgreSQL Docker CI/CD

2021 — 2023

Tech Lead | Senior Python Engineer — Globaldev Group

OwnedApplication design, architecture and technical direction on a wealth-management platform for financial advisors. Risk management, feature estimates and release planning, continuing with the Steelkiwi team after Globaldev's 2021 acquisition.

Helped scale the engineering team from 5 to 20+ — interviewing, onboarding and technical ramp-up
Contributed to ISO 27001 certification — security controls in application architecture and data handling
Refactored the legacy internal CRM — structural and architectural rework plus database optimization
Defined business requirements directly with the CTO, product owner and stakeholders

Python Django Django REST Framework Celery PostgreSQL Redis Docker AWS

2017 — 2021

Python Developer → Tech Lead — Steelkiwi Inc.

OwnedA Python CRM platform for an Australian fintech — client management, authentication, granular permissions and secure data processing. Grew from developer to Tech Lead over four years on the account.

Built data synchronization handling 500K+ records per day across third-party financial integrations
Cut the bug rate by 30% and shortened delivery cycles by tightening the SDLC — review standards, automated testing and release process
Extended the core engine with Stripe, Xplan, Google and AWS integrations; built payment processing and financial data flows
Contributed to ISO 27001 certification

Python Django Django REST Framework Celery PostgreSQL Redis MySQL Docker AWS

2016 — 2017

Python Developer — CryptoTrade

OwnedBackend features on a crypto-trading monolith with real-time peer-to-peer transactions — the first production system where I owned features rather than tickets.

Backend development in Python and Django across the trading platform
Unit testing with pytest, and working requirements into defined scope with the client

Python Django PostgreSQL

Skills & tools

Years, last used, and the projects that prove it. Last used is derived, not self-declared.

Backend

Python 11 yrs 2026 5 projects

Django 9 yrs 2026 4 projects

Django REST Framework 9 yrs 2025 4 projects

FastAPI 2 yrs 2026 1 projects

Celery 9 yrs 2026 5 projects

AI & LLM

OpenAI / Azure OpenAI 2 yrs 2026 4 projects

Claude 2 yrs 2026 3 projects

LangChain 2 yrs 2026 1 projects

LangGraph 2 yrs 2026 1 projects

MCP servers 1 yrs 2026 1 projects

RAG & hybrid search 2 yrs 2025 3 projects

Computer vision (YOLO, OpenCV) 1 yrs 2025 1 projects

Data & storage

PostgreSQL 9 yrs 2026 5 projects

pgvector 2 yrs 2026 2 projects

Qdrant 1 yrs 2026 1 projects

Redis 9 yrs 2026 5 projects

MySQL 9 yrs 2019 1 projects

Infrastructure

Docker 9 yrs 2026 5 projects

AWS 9 yrs 2026 5 projects

Azure 2 yrs 2026 0 projects

CI/CD 9 yrs 2025 5 projects

Kubernetes 2 yrs 2024 0 projects

Frontend

JavaScript 9 yrs 2025 4 projects

Vue 5 yrs 2021 0 projects

React 2 yrs 2026 4 projects

Education

Diploma in Information TechnologiesVinnytsia IT Academy · 2015–2016

MSc, EcologyVinnytsia National Agrarian University · 2008–2013

Certifications

The Complete Web Development BootcampBogdan Stashchuk · 2024-02

AWS Cloud Technical EssentialsAmazon Web Services · 2024-02

Languages

English — C1
Ukrainian — native

Bio & headshot

For organisers and decks. Copy either version; the portrait is free to use.

Short

Stanislav Rybonka is a Python engineer specialising in backend and AI systems. Over ten years he has built production systems for fintech, enterprise and SaaS companies, led teams as Tech Lead, and now runs Flexipy OÜ, a Python engineering company shipping AI-powered platforms to production.

Long

Stanislav Rybonka is a Python engineer based in Vinnytsia, Ukraine, specialising in backend and AI systems. Over ten years he has grown from developer to Tech Lead, scaling an engineering team from five to twenty-plus, and has built production systems for an Australian fintech, an Israeli wealth-management platform and an enterprise whistleblowing platform used by Fortune 100 companies and government agencies. He is now founder and principal engineer at Flexipy OÜ, an Estonian company shipping AI-powered SaaS, agent systems and MVPs — four LLM platforms delivered to production in eighteen months, including an agent OS running 25+ specialist agents under a human-approval workflow. He writes about the architecture decisions behind that work at stan.rybonka.tech, and speaks English and Ukrainian.