Sviatoslav

Lviv, Ukraine, 2026
[open contact info](look above in the "contact info" section)
[open contact info](look above in the "contact info" section)

Sviatoslav Sabadosh
Backend PHP Engineer with 9+ years of experience designing scalable backend systems and
distributed architectures. Specialized in Laravel, Symfony, and Unix environments, with strong
expertise in Software Architecture, Domain-Driven Design, and high-performance system design.
Experienced in building modular monoliths and microservice-based systems, applying distributed
architecture patterns such as CQRS, SOA and Event-Driven Architecture.
Focused on clean/hex architecture, maintainable systems, and translating complex business
domains into robust software models. Actively contribute to architectural standards, code
quality improvements, and cross-team technical collaboration.
Open to technical discussions and knowledge sharing — while keeping a bit of humor in the
team.

SKILLS
🧩 Software Architecture & Design
● Domain-Driven Design (Strategic & Tactical patterns)
● Clean Architecture & Hexagonal Architecture
● Context Mapping (Anti-Corruption Layer, Shared Kernel, Conformist)
● Modular Monolith & Microservices Architecture
● CQRS and Event Sourcing patterns
● Event-Driven Architecture and asynchronous system design
Strong understanding of SOLID, GRASP, and object-oriented design principles
● Design Patterns, Dependency Injection, Repository & Specification patterns

💻 Backend Development
● Experience designing high-load and scalable backend systems

● PHP 8+, Laravel, Symfony
● REST API design and distributed service integration
● GraphQL APIs
● PSR-12 compliant codebases and clean code practices
● PHPUnit, Test-Driven Development (TDD), mocking and test strategies
● CI/CD pipelines (GitLab CI, GitHub Actions)
● Extensive experience with DDD modules, Application Services, Domain Events and

🧠 Database, Search & Caching
repositories

● MySQL, PostgreSQL, MongoDB
● Query optimization, indexing strategies, partitioning
● Query plan analysis and database performance tuning

📡 Messaging & Event Streaming
● Redis, Memcached for caching and distributed coordination

● RabbitMQ, Apache Kafka
● Event-driven communication between services

🤝 Leadership & Collaboration
● Designing asynchronous workflows and distributed messaging patterns

● Contributor to architecture guidelines and coding standards
● Driving DDD, SOA and Clean Architecture adoption across teams
● Technical mentoring and cross-team collaboration
● Writing architectural documentation and knowledge sharing (Confluence)

EXPERIENCE
Decision Engine (Realtime Workflow)
Lead Software Architect / R&D Engineer (Highload Platforms) | Stealth Mode Tech
Mar 2026 - Present
Business Summary: A real-time decision engine designed to automate and optimize critical
business operations across fraud prevention, approval workflows, dynamic pricing, eligibility
checks, and quota control. The platform evaluates transactions and business events by
combining deterministic business rules, contextual feature analysis, and ML scoring to produce
fast, explainable, and fully auditable decisions.
Technical Overview: Built on PHP 8.4 and Symfony using Domain-Driven Design (DDD) and
Hexagonal Architecture to ensure clean separation of concerns and high maintainability. The
platform leverages react runtime (FrankenPHP) and async/event-driven patterns for
high-performance processing, Redis for ultra-low latency caching and feature retrieval,
PostgreSQL for robust multi-tenant data persistence, and Docker for environment consistency.
• Designed and developed a high-throughput, multi-tenant Real-Time Decision Engine from
scratch to automate critical business operations including fraud detection, dynamic pricing,
eligibility checks, and scoring.
• Applied Domain-Driven Design (DDD) principles, establishing clear Bounded Contexts for the
core system (Decision), factor analysis (Feature), business rules (Ruleset), and ML models.
• Implemented hybrid decision-making logic combining a deterministic rule-based engine with
AI/ML scoring, integrating a strict explainability module and comprehensive audit trails for
compliance.
• Built an asynchronous architecture powered by modern PHP 8.4 and high-performance
application servers (FrankenPHP), minimizing server response time (TTFB) to 1 milliseconds in
high-throughput scenarios.
• Architected data persistence and traffic control infrastructure utilizing PostgreSQL, Redis,
rate limiting, and quota management to ensure strict multi-tenant data isolation and stability
under peak stress loads.
• Developed business experimentation tools, including advanced user segmentation modules and
intelligent traffic routing for comprehensive A/B policy testing (Experiment Engine).

Medical Network, Product Company, (medblu.net), Canada, Ukraine
Senior Backend Developer
Dec 2025 - Mar 2026
Integrated Stripe payment workflows, implementing hold, release, and capture flows for secure
transaction processing.
Collaborated closely with multiple microservices, ensuring stable service communication and
data consistency across the platform. Improved the existing component-based architecture,
enhancing maintainability and modularity of the system.

AUTODOC, Product Company, (autodoc.pro), Kiev, Odessa
Senior Backend Developer
Apr 2022 - Oct 2025
Worked on Loyalty and Refund (Returns) Context, developing features for customer rewards and
refund processing. Laravel based application with MySql database. The project infrastructure
is built on Google Cloud Platform (GCP). Also developed an internal Role & Permission
Management System to simplify access control across services, which was recognized and
rewarded by the company.
Introduced a unified testing concept across teams, establishing best practices for unit
testing and improving overall code reliability and test coverage.
Later joined the Catalog & Search team (Core/Support Domain), contributing to product data
performance, filtering improvements, and the transition toward a microservice architecture.
Actively evaluated and applied Clean Architecture principles during the migration process!
Implemented GitLab CI/CD pipelines for automated testing, code quality checks, and deployment
workflows. Configured test coverage badges and pipeline status reports for visibility across
teams.

Sihmetiks, Product Company, (unionstreetmedia.com), Ivano-Frankivsk, USA
Senior FullStack Developer
Jan 2020 - Feb 2022
Developed and maintained full-stack features for a real estate marketing platform, focusing on
data synchronization and filtering from one of the largest U.S. real estate data providers via
API integration. The project infrastructure is built on Amazon Web Services (AWS).
Built React.js filtering front interfaces and backend logic in Laravel with MySQL, ensuring
reliable data import and consistent property listings. Provided cache to improve performance
of query listing data on Redis.

Patron Empowerment, Product Company, (rhythmic-rebellion.com), Kharkiv, GA, USA
Middle Backend +
Oct 2019 - Dec 2019
Maintained and improved Laravel-based backend microservices for music archive generation and
user notifications. The project infrastructure is built on Amazon Web Services (AWS).

GRTCompany, Outstaff, Ivano-Frankivsk
Middle FullStack Developer
Sep 2017 - Oct 2019
Developed interactive web applications. Built solutions using Laravel, Vue.js/AngularJS,
MySQL, and GraphQL, including online tour registration systems, custom web stores, and online
creative banner/logo constructors based on JS.

SPDEVCompany, Outsource, Ivano-Frankivsk
Junior FullStack Developer | Middle Backend +
Jun 2016 - Sep 2017
Development of online stores, blogs, landing pages, business cards. Also developed a local
Bitcoin exchange gateway between credit cards and crypto wallets, and a warehouse scanning app
for internal logistics operations.