Roman L.

Senior .NET developer for legacy modernization, API performance and architecture reviews. I help teams make slow, fragile .NET products stable and ready to scale. Many teams run into the same issues as they grow: slow APIs, fragile integrations and a codebase that gets harder to change every month. I solve these problems early by building robust backend systems and scalable architecture that hold up in production. I'm a .NET Developer and Full Stack Developer with 8+ years of commercial experience building secure, high-performance web applications with .NET and Angular, focused on clean architecture, maintainability and long-term product growth. How I help - Modernizing legacy .NET systems and moving them to the cloud - Architecture reviews and technical audits of existing codebases - Designing and optimizing high-performance APIs and backend services - Integrating external APIs and business systems - Building Angular frontends and SaaS features when you need a Fullstack Angular Developer Experience - 10+ years of commercial experience in .NET development and technical leadership - 100% Job Success on Upwork, 601+ hours delivered, $20K+ earned - 100+ projects delivered with my Intelvision engineering team over the last 5 years - Worked with Visoplan, ING+, Jincom, Kiflo and other SaaS and enterprise products. Many clients return for additional work once their systems start scaling. Stack Backend: C#, .NET / ASP.NET Core, Web API, SignalR, Microservices Frontend: Angular, TypeScript, SPA architecture Databases: PostgreSQL, SQL Server, Redis Cloud and DevOps: Azure, AWS, Docker, Kubernetes, CI/CD pipelines Architecture: RabbitMQ, Hangfire, MediatR, Elasticsearch, GraphQL Integrations: Stripe, Xero, QuickBooks, Microsoft Graph API, Salesforce, SAP / Dynamics Security: OAuth2, JWT, Auth0, Azure AD B2C, secure cloud key management Industries: SaaS, FinTech, PropTech and ConTech, logistics platforms, custom enterprise software How I work I prefer long-term partnerships where I take ownership of architecture and delivery, but I'm also happy to help with specific tasks such as feature development, system audits or architecture improvements. The goal is always software that works reliably in production and supports business growth. Education: Bachelor's degree, Software Engineering, Lviv Polytechnic National University. Certifications: .NET Core Architecture; Angular Frontend Engineering. If you're modernizing a legacy platform or scaling an existing product, send me a message. I'll review your architecture and suggest a practical technical approach. 08/10/2026