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Viktar Dubiniuk

Backend Engineer · Go · PHP · Linux Systems

Warsaw, Poland

Backend Engineer with 15+ years across Go, PHP, and Linux infrastructure. Experienced in owning core systems, modernizing legacy codebases, and database optimization. Grounded in Linux internals and operational reality - focused on shipping clean, deterministic Go code and maintaining long-lived production systems without unnecessary complexity.

Engineering Experience

Senior Software Engineer

B2B SaaS (NDA) · Jul 2025 — Present · Part-time · Remote

Built an LLM credit system in Go — usage tracking, period refills, one-time top-ups via Stripe Checkout, idempotent grant logic.
Designed modular CloudFormation stacks on ECS Fargate + Lambda; unified dev/prod environments.
CI/CD with GitHub Actions (reusable workflows, OIDC), IAM/SSM secrets, RDS/Redis/SQS, health checks and structured logging.
Shipped Stripe subscriptions and checkout — webhooks, promo codes, billing state sync (Python/FastAPI).

Software Engineer

ownCloud · Contract · Jun 2013 — Jul 2021 · Part-time · Remote

Public contribution history only — private ownCloud Enterprise repositories are excluded.

Evolved from a community contributor in January 2012 into a Core Team Engineer, driving development for both the open-source platform and the ownCloud Enterprise product line.
Represented ownCloud in the design of the OpenCloudMesh (OCM) 1.0 protocol. Implemented OCM 1.0 to enable cross-platform federated file sharing.
Developed and maintained critical backend components, including the web update engine, database abstraction layer (MySQL, PostgreSQL, OracleDB), and templating subsystem.
Architected and delivered data retention policies for versioning and trashbin subsystems.
Refactored barracudanetworks/archivestream-php package for ownCloud to ensure PSR-4 compliance and clean Composer integration.
Took ownership of key community and enterprise applications, ensuring the stability of plugins like files_antivirus, files_pdfviewer, and documents.
Implemented WebDAV complex properties support.
Systematically improved backend reliability by expanding unit (PHPUnit) and acceptance (Behat) test coverage. Collaborated daily within a multicultural, globally distributed team using a PHP (Symfony/Doctrine) and JS (Vue.js/AngularJS) stack.

Software Engineer

Aheadworks · Aug 2008 — Present · Remote

One employer — internal role progression over 18 years across backend engineering, Linux systems, and infrastructure.

DevOps Engineer

Nov 2019 — Present

Sole ownership of full lifecycle of regional branch infrastructure on Linux.
Audited and migrated acquired PHP/Laravel applications into the company’s standardized environment.
Built and managed deployment environments with Docker Compose for microservice-oriented projects.
Standardized CI/CD for 60+ Magento extensions and 15+ Laravel SaaS products.
Developed internal automation toolkits in Python and GNU Make for testing and environment provisioning.
Configured Traefik and Nginx reverse proxies for high availability and SSL termination.

Systems & Web Engineer

Jun 2013 — Oct 2019 · Part-time · Hybrid

24/7 technical ownership of the primary revenue-generating Magento extensions store.
Integrated and customized internal products into the store; enhancements adopted into the core product line.
Executed infrastructure migrations across dedicated servers; bare metal to VPS using OpenVZ and LXD.
Reported directly to company owners, aligning technical roadmaps with business goals.

Full Stack PHP Developer / SysOps (Lead)

Jul 2011 — May 2013 · Full-time · On-site

Managed a cross-functional operations team (backend and frontend developers).
Led the technical transition from traditional sales to SaaS, boosting recurring revenue.

Full Stack PHP Developer

Aug 2008 — Jul 2011 · Full-time · On-site

Key contributor as the company scaled to its first $1M in annual revenue.
Built turnkey solutions, custom features, and themes for the X-Cart and Magento ecosystem.

Technical proficiencies

Go — concurrency, HTTP services, systems daemons
Linux — Netlink, cgroups, systemd, openSUSE since 2007
HTTP — middleware design, load shedding, back-pressure
AWS — ECS Fargate, Lambda, RDS, SQS, CloudFormation
Platform — Docker Compose, CI/CD, bare-metal provisioning

Selected Go projects

shedder-shredder
Priority-based load shedding for http.Handler chains — back-pressure under saturation.
go-powerd
Netlink-driven battery daemon, ~12MB RSS, fully static binary with systemd integration.
vakula
File-triggered worker with Docker-sandboxed Go execution and validated project export.
sway-icon-to-go
Event-driven Sway workspace renaming with Font Awesome icons and LRU-cached app lookup.

Selected training

Go

Go Backend Masterclass — Three Dots Labs (Apr 2026)
Advanced Golang — KodeKloud (Mar 2026)
Design Patterns in Go — Udemy (Dec 2025)
API Development and Documentation using Go — Udacity (Mar 2025)

Platform & DevOps

Cloud DevOps Engineer — Udacity (Feb 2025)
AWS Cloud Practitioner Essentials — AWS (May 2025)
Modern CI/CD with GitLab — Udemy (May 2024)

Languages

EF SET English Certificate — 78/100 (C2, reading & listening) — EF SET (Jun 2024)

Education

M.Sc. Physics & IT — Brest State University

Languages & logistics

Languages: English (C1 overall), Polish (B1), Belarusian (native), Russian (native), Ukrainian (fluent)
Location: Warsaw — no relocation
Legal: Residence permit until mid-2027. Work permit required for direct employment (oświadczenie).
Availability: B2B (via payroll company) or UoP/UZ