Сергій

Serhii Matviienko
Senior / Lead Backend Engineer (Python)
Kyiv, Ukraine (open to remote)
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Professional Summary
Senior Backend Engineer with ~20 years of experience building and operating high-scale distributed
systems across cybersecurity SaaS and ML/model-training infrastructure. Strong track record in diagnosing
complex multi-service production issues, optimizing infrastructure, and designing backend systems that
improve reliability, developer workflow, and operational efficiency. Deep Python expertise combined with
Kubernetes, microservices, CI/CD, and production-grade system design mindset.

Core Skills
Backend & APIs
Python, Django, FastAPI, Flask, REST, async/await, FastMCP, Go

Distributed Systems
Microservices, Kafka, Redis, caching strategies, event‑driven architectures

ML / AI Infrastructure
Model training infrastructure, LLM tooling, training pipelines, GPU training environments

Data & Storage
PostgreSQL, MongoDB, MySQL, S3

Infrastructure & DevOps
Kubernetes, Docker, AWS, CI/CD, UWSGI, Linux

Quality & Observability
pytest, TDD, code reviews, Elasticsearch/Kibana, monitoring, NewRelic

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Professional Experience

Imubit — Senior Software Engineer

Jan 2026 – Jul 2026
Algo R&D group working on model training infrastructure and internal engineering tools.

• Designed and delivered core parts of Algolib 3, a next-generation model training library, including
training flow architecture, storage adapters, integration with internal model-management services,
CI/CD, observability, tests, and documentation
• Authored a high-level design for the Algolib 3 training flow and turned it into an end-to-end
implementation used as team reference material
• Built a Go-based internal service enabling natural-language queries over model statistics data,
applying modern LLM tooling and Kubernetes deployment practices
• Improved ML training infrastructure by re-architecting GPU training images to reduce image size and
build time
• Refactored the S3 access layer and streamlined CI configuration to improve maintainability and
developer workflow
• Collaborated closely with DevOps, platform, and product stakeholders while sharing knowledge
across the Algo R&D group n

Cyberint (Check Point Software Technologies) — Senior Software Engineer

Feb 2024 – Jan 2026
Cybersecurity SaaS platform for External Risk Management (Attack Surface Management, Threat
Intelligence, Brand Protection).

• Reduced alert false positives by 40%+ by implementing EPSS-based filtering, CVSS network-vector
validation, and contract-aware suppression logic across Django microservices
• Diagnosed and resolved critical alert-closure failures by tracing data flow across a 6-microservice
architecture and validating database integrity constraints
• Delivered 8×–24× throughput improvements in discovery jobs by identifying UWSGI single‑worker
bottlenecks and aligning Kubernetes and client concurrency settings
• Designed and implemented a multilevel caching utility (in‑memory → Redis → service fallback)
with async/sync interfaces and thread‑safe behavior
• Architected Kafka‑based technology detection pipelines integrating multiple third-party detection
tools and data sources, documenting end‑to‑end data flows and precedence rules

Intuition Machines — Senior Software Engineer

Jun 2021 – Oct 2023
Company behind hCaptcha, providing large‑scale ML‑based bot and fraud protection.

• Built and supported backend services processing millions of events in a distributed environment

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• Implemented event‑driven communication patterns between microservices
• Improved developer productivity by optimizing Docker images, CI/CD pipelines, and local
development environments
• Consolidated multiple related repositories into a single codebase while preserving full commit
history
• Mentored engineers, performed code reviews, and supported cross‑team engineering initiatives

StarOfService — Backend Team Lead / Senior Backend Engineer

Nov 2016 – Jun 2021
Global marketplace platform operating across 130+ country‑specific deployments.

• Led and mentored a backend team of 5–10 engineers
• Planned and delivered API‑first features following JSON\:API principles
• Migrated legacy systems from Symfony 1.5 to Symfony 4
• Consolidated 130+ country databases into a centralized, replicated AWS architecture
• Owned backend delivery, release processes, and production stability

Earlier Experience
Freelance Web Developer — 2005–2016
Full‑cycle web development, custom CMS/CRM systems, VPS administration, multiple PHP frameworks and
platforms.

Web / Frontend Developer — 2002–2005
PHP, Java, HTML/CSS/JavaScript, e‑commerce platforms, CMS development.

Education & Certifications
National Technical University of Ukraine “Kyiv Polytechnic Institute”
Engineer’s Degree & Bachelor’s Degree — Telecommunications Systems

EF SET Certificate — English Level C2

Additional Notes
• Strong production ownership and systems‑level thinking
• Comfortable operating in high‑ambiguity, high‑impact environments
• Open to Senior, Lead, or Staff‑level backend roles

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