Sebastian Luchian
I build and troubleshoot production software, APIs, integrations, and data-driven systems across .NET and SQL. I build and troubleshoot production software, APIs, integrations, and data-driven systems across .NET, SQL, and industrial environments.
Based in Iasi, Romania. Open to employment, B2B, remote, hybrid, or relocation-based roles. software systems engineer . Based in Iasi, Romania. Open to software engineering, systems, integration, and technical engineering roles - employment or B2B, remote, hybrid, or relocation.
Software systems
.NET · SQL · APIs · Integrations
Production .NET systems
Backend work on live business applications
SQL-backed business logic
Queries, reporting, data access and issue analysis
Caching & state handling
Redis and CMS cache usage in production flows
Full-stack support
React/TypeScript when delivery needs it
Now
- Building Production .NET APIs and SQL-backed services for an e-commerce platform
- Reading EF Core performance docs and Application Insights query recipes
- Open to software, systems, integration, and .NET-heavy roles now
updated 1 weeks ago
About
Software and systems engineering for production environments.
My strongest work sits where software meets operational reality: C#/.NET, SQL, APIs, integrations, production troubleshooting, automation, and maintainable business systems.
- Professional software experience since 2022 across production systems, business applications, integrations, and SQL-backed workflows.
- Strongest in C#/.NET, SQL, REST APIs, production troubleshooting, data access, caching, and maintainable business logic.
- Comfortable investigating issues across logs, SQL, Redis/cache state, APIs, Application Insights, Postman, Ghost Inspector, and request-level behavior.
Experience
Software and systems engineering work
Confidential Company · Iasi, Romania
Internal software and systems work across Python data collection, production dashboard maintenance, database troubleshooting, operational workflows, and implementation planning for internal applications.
- Designed and implemented automated data collection pipelines for third-party online platforms, handling extraction, normalization, persistence, and reporting data used by internal workflows.
- Refactored a production Python dashboard application by restructuring legacy components and improving maintainability, reliability, and ease of future development.
- Maintained and troubleshot an existing production database, investigating data inconsistencies, application errors, and operational issues.
- Analyzed business and operational requirements and translated them into technical implementation proposals for internal applications and system improvements.
- Diagnosed and resolved cross-functional technical issues affecting applications, internal users, and day-to-day operations.
Software Engineer / .NET Backend Developer · Iasi, Romania
Production software engineering work across .NET, SQL-backed business systems, REST APIs, integrations, production troubleshooting, internal tools, automation, industrial data collection, and practical full-stack delivery when needed.
Production engineering
- Worked on a live UK e-commerce/CMS platform built with ASP.NET, .NET Framework 4.8, SQL Server, Umbraco CMS, Redis, AngularJS, React, and Razor/CSHTML.
- Took ownership of production-critical tasks across backend investigation, SQL-backed issue analysis, release validation, customer-support escalations, and targeted fixes.
- Used Application Insights, logs, local debugging, database inspection, Postman, Ghost Inspector, and request-level analysis during dev-on-duty work.
- Improved cart workflows, Redis/Umbraco cache behavior, LINQ/SQL paths, and selected Entity Framework query patterns.
Delivery & business context
- Built back-office and reporting features, CSV exports, SQL views, marketing/engagement integration support, and external platform data flows for business users.
- Supported external API notifications and Stripe/NestJS subscription lifecycle flows.
- Supported releases and customer-support escalations while keeping release safety and business impact in mind.
Full-stack support when needed
- Built React/TypeScript features from Figma designs and bundled Webpack output into legacy ASP.NET/CSHTML views.
- Maintained AngularJS, jQuery, Razor/CSHTML, and CMS-backed interfaces connected to existing .NET functionality.
Projects
Backend systems, workflows, and product delivery
Selected work across production e-commerce, document workflows, operational reporting, SQL-backed logic, APIs, and business-facing backend systems.
Production e-commerce platform work involving cart and checkout workflows, subscription state, Redis/Umbraco cache issues, Stripe-related middleware flows, external API notifications, reporting, CSV exports, back-office tooling, and cart workflow improvements.
Support-to-release flow
Problem
Cart, checkout, CMS/admin, integrations, and reporting flows had to stay reliable under real customer and support pressure.
What I built
Investigated production issues through logs, Application Insights, SQL queries, Redis/Umbraco cache checks, Postman/Ghost Inspector validation, and targeted backend fixes.
Result
More reliable production flows, faster issue investigation, and safer changes in legacy .NET Framework code.
- .NET Framework 4.8 ·
- SQL Server ·
- Umbraco CMS ·
- Redis ·
- Stripe flows
- +5
Built a document workflow proof-of-concept from scratch with ASP.NET Core, PostgreSQL, EF Core, JWT authentication, permission-key authorization, audit history, reporting, batch attachments, and a React frontend. The system modeled department-based document routing with forward/back/complete/close actions and sensitive document access rules.
Workflow backend
Problem
Documents needed department-based routing, permission checks, attachments, reporting, and traceable workflow decisions.
What I built
Built an ASP.NET Core/PostgreSQL PoC with permission-key authorization, workflow actions, audit, reports, batch attachments, and React screens.
Result
Presented a client-facing proof-of-concept with a complete workflow model and working frontend.
- ASP.NET Core ·
- React ·
- PostgreSQL ·
- EF Core ·
- JWT
- +1
Built a tenant-aware ASP.NET Core backend prototype with PostgreSQL, EF Core, JWT refresh tokens, permission management, runtime configuration APIs, and a React admin UI. The project explored multi-tenant backend architecture, admin/runtime API separation, and config-driven runtime behavior.
Platform architecture
Problem
A backend platform needed separated admin/runtime concerns, tenant-aware behavior, permissions, and SQL-backed persistence.
What I built
Built a tenant-aware ASP.NET Core backend prototype with EF Core, JWT refresh tokens, permission management, runtime APIs, Docker, and a React admin UI.
Result
Demonstrates modular .NET backend design, admin/runtime API separation, persistence, and configuration-driven runtime behavior.
- .NET ·
- ASP.NET Core ·
- EF Core ·
- React ·
- TypeScript
- +1
Additional engineering work
Additional technical work
Smaller or more focused work that shows range across automation, systems, migration, and academic engineering projects.
Built Python collectors and a Flask reporting dashboard that centralized operational data from multiple external platforms. The system used APIs, Selenium crawlers, cron jobs, user management, reporting, and bonus/malus calculations to replace manual checking and provide unified month-to-month comparisons.
- Python ·
- Flask ·
- PostgreSQL ·
- Selenium ·
- Cron jobs ·
- Reporting
Worked on a PHP 7 to PHP 8 migration and implemented scoring logic for matching real estate offers against client preferences such as budget, area, rooms, and surface. Also handled UI bugfixes and compatibility issues caused by stricter PHP 8 behavior.
- PHP 7 ·
- PHP 8 ·
- MS SQL ·
- Scoring Logic ·
- Real Estate
Contributed to an NDA-covered enterprise medical/insurance workflow desktop application used by insurance operations teams. The system combined an Electron shell, Angular frontend, Java/Spring Boot microservices, REST APIs, PostgreSQL, MinIO-backed document storage, and XML-based document generation.
- Java ·
- Spring Boot 3 ·
- Angular ·
- Electron ·
- PostgreSQL ·
- MinIO
Worked on an industrial data collection/reporting project for a pipe production line. Collected PLC production data into SQL Server, built AVEVA/Wonderware screens and data views, and translated client requirements into reporting and data collection logic.
- AVEVA Wonderware ·
- Visual Basic ·
- MS SQL ·
- PLC Data
Worked on configuration-driven iGaming slot projects using C++, Python tooling, Excel math sheets, and RTP simulation workflows. Converted mathematician-provided game definitions into runtime configuration, validated behavior through simulations, and fixed configuration or game-related issues.
- C++ ·
- Python ·
- Game Logic ·
- RTP Simulation ·
- Slots
Academic SystemC project simulating packet routing across configurable router networks, including CPU-to-memory transactions, multi-router topologies, YAML-driven configuration, routing policies, and TTL handling.
- SystemC ·
- C++ ·
- CMake ·
- YAML ·
- Routing Simulation
How I think about backend systems
From business rules to production backend systems
I focus on backend systems where correctness, maintainability, data consistency, and production debugging matter.
Requirements, implementation, data, and production feedback
01
Product requirements
Business rules, support tickets, admin needs, edge cases
02
ASP.NET APIs
REST endpoints, validation, auth, integrations, webhooks
03
Business Services
Cart, checkout, workflows, reporting, admin operations
04
Data Layer
SQL Server, PostgreSQL, EF, LINQ, Redis/cache state
05
Production feedback
Logs, App Insights, Postman, Ghost Inspector, support follow-up
What I try to make visible in backend work
Traceability
Audit logs, request states, Application Insights traces, API checks, and reproducible support cases.
Data correctness
SQL-backed business rules, EF mappings, Redis/Umbraco cache checks, and regression-conscious fixes.
Operational feedback
Support tickets become debugging paths, targeted fixes, and release-safe improvements.
Tech
Tech stack
C# · .NET Framework · .NET · ASP.NET Core · REST APIs · JWT authentication · authorization · SQL Server · PostgreSQL · Entity Framework · EF Core · LINQ · SQL · Redis · caching · SQL/LINQ query tuning · React · TypeScript · AngularJS · JavaScript · Razor · CSHTML · jQuery · Webpack · Umbraco CMS · HTML · CSS · Git · Docker · Swagger/OpenAPI · Application Insights · Azure release support · Postman · JMeter · Ghost Inspector · Python · Flask · Selenium · BeautifulSoup · C++ · Java · Spring Boot
Backend
- C# ·
- .NET Framework ·
- .NET ·
- ASP.NET Core ·
- REST APIs ·
- JWT authentication ·
- authorization
Data
- SQL Server ·
- PostgreSQL ·
- Entity Framework ·
- EF Core ·
- LINQ ·
- SQL ·
- Redis ·
- caching ·
- SQL/LINQ query tuning
Web/CMS
- React ·
- TypeScript ·
- AngularJS ·
- JavaScript ·
- Razor ·
- CSHTML ·
- jQuery ·
- Webpack ·
- Umbraco CMS ·
- HTML ·
- CSS
Tools
- Git ·
- Docker ·
- Swagger/OpenAPI ·
- Application Insights ·
- Azure release support ·
- Postman ·
- JMeter ·
- Ghost Inspector
Other
- Python ·
- Flask ·
- Selenium ·
- BeautifulSoup ·
- C++ ·
- Java ·
- Spring Boot
Certifications
Certifications & learning
NVIDIA Deep Learning Institute
Education
Engineering foundation & languages
Gheorghe Asachi Technical University of Iasi
Gheorghe Asachi Technical University of Iasi
Power Electronics and Electrical Drives program covering static power converters, electric drives, programmable logic controllers, distributed control systems, industrial informatics, and industrial robots.
Communication level
Available now for employment or B2B contract roles across software engineering, systems, integration, and technical engineering work. Open to remote, hybrid, or relocation-based work.
For software engineering, systems, integration, or backend-heavy .NET roles, contact me by email or LinkedIn.
[email protected]