The system is hard to change
Production issues, tangled logic, outdated dependencies or a new capability that must fit an existing application without destabilizing adjacent workflows.
Software architecture · Backend · Applied AI
Software Architect & Senior Backend Engineer
I design and improve the systems businesses rely on.
I help teams understand working systems, remove technical constraints and deliver the changes the business needs — grounded in the code, data, integrations and infrastructure.
- Software engineering
- 15+ years
- Across connected systems
- Code · Data
- From investigation to delivery
- Build · Improve
When I can help
The starting point is not a technology list. It is a business workflow, a system constraint or a change that needs to become manageable.
Systems need to work together
ERP, CRM, commerce, supplier and external services connected through explicit APIs, adapters, data flows and event processing; web-application integration with a telephony platform.
Knowledge is difficult to find
Data search and indexing, Elasticsearch index, query and relevance tuning; AI assistants that retrieve company information, assemble useful context and return answers with source references.
The web application needs reliable operations
Administration of application environments, production and staging setup, local development, server and application monitoring, performance diagnostics and coordinated upgrades.
Scope of work
A focused change, not a predetermined package.
The useful outcome may be a diagnosis, an architecture decision, an implementation or a staged modernization. The scope follows the system and the result required.
Technical investigation
Trace actual behavior across application code, data, integrations and operations; identify constraints, risks and the likely source of the problem.
Architecture and plan
Define component responsibilities, data flows, integration contracts, acceptance criteria and a practical sequence of changes.
Implementation
Build the backend, API, integration, search, AI workflow, background processing or client capability needed for the agreed result.
Modernization and reliability
Upgrade a framework or runtime, isolate fragile areas, remove a bottleneck and improve diagnostics without assuming a full rewrite.
Environments and monitoring
Configure production and staging environments, reproducible local development, web and application services, health checks, server monitoring and actionable alerts.
Verification and handover
Check the agreed behavior, deployment and recovery path, and leave clear technical context for continued ownership.
A rewrite remains an option when the business case supports it, not the default answer to an unfamiliar or aging system.
Managed web operations
Subscription support for servers and web applications.
A defined operations scope for companies that need ongoing technical ownership without building a full in-house application operations function. It starts with an inventory and a stabilization backlog, then combines monitoring, planned maintenance and incident handling within agreed service hours.
Explore support plansMonitor
Health checks for the server, HTTPS and agreed application components, actionable alerts and a concise monthly report with risks and next priorities.
Maintain
Monitoring plus planned operating-system, runtime and dependency updates, compatibility checks, recovery checks and a bounded monthly maintenance capacity.
Priority response
Prioritized triage of critical incidents and confirmed threats during agreed hours, with containment or rollback coordination and a documented follow-up backlog.
Co-managed support
L2/L3 application operations support for an internal team: difficult diagnostics, coordinated upgrades, configuration review, runbooks and knowledge transfer.
Monitoring does not automatically mean 24/7 human on-call. Exact systems, response windows, emergency capacity and ownership are agreed after onboarding; no blanket uptime or recovery promise is implied.
How I work with a system
Each engagement follows the same principle: understand the real behavior first, then make the smallest responsible change that achieves the required outcome.
Understand the current behavior
Trace a real business workflow through the application, data, integrations and operations. Separate verified observations from assumptions before proposing changes.
Define a practical scope
Agree on the outcome, constraints and acceptance criteria. Choose a focused intervention that fits the system instead of defaulting to a rewrite.
Implement the change
Build within the agreed scope, with diagnostics, deployment and recovery in mind rather than treating delivery as code alone.
Verify and hand over
Check the result against the agreed behavior and leave the system, documentation and technical context easier to support.
Technical range
Technologies support the solution; they do not define it. The exact stack depends on the existing system and the change being made.
Applications
Backend services, web interfaces and mobile clients with PHP, Python, Laravel, Django, FastAPI, Angular, React.js, Nuxt.js, Vue.js and Flutter.
Data and search
PostgreSQL, MySQL, Oracle, Redis, queues, Elasticsearch and Qdrant where they fit the project.
Integrations
REST, SOAP, WebSocket, SSE and event-driven flows across ERP, CRM, commerce, supplier, telephony and external services.
Applied AI
Document ingestion, hybrid retrieval, RAG, source-backed answers, LLM integration and tools that assemble inspectable project context.
Web application administration
Linux, Docker, Nginx or Apache, TLS and the databases, caches, queues and search services around an application; production, staging and reproducible local development environments.
Monitoring and diagnostics
Server and web-application health checks, Zabbix monitoring, Telegram alerts, logs and measurement-led diagnosis across the application, database, cache, queues, search and web server.
About
A system-wide engineering perspective.
I am Oleksandr Zahoruiko, a Software Architect and Senior Backend Engineer with 15+ years in software engineering.
My work spans backend development, architecture, integrations, data systems, application operations and technical leadership. I am comfortable entering an unfamiliar system and tracing how business behavior is distributed across code, data and infrastructure.
I work with existing systems as well as new capabilities. The aim is a bounded, maintainable change with clear verification and enough technical context for the team that owns it next.
Tell me what needs to work.
Share the business goal, the current system and the difficulty you want to resolve.