Lead .NET Architect (System Modernization & AI Integration)

Company Description

As Hungary’s most attractive employer in 2025 (according to Randstad’s representative survey), Deutsche Telekom IT Solutions is a subsidiary of the Deutsche Telekom Group. The company provides a wide portfolio of IT and telecommunications services with more than 5300 employees. We have hundreds of large customers, corporations in Germany and in other European countries.

DT-ITS recieved the Best in Educational Cooperation award from HIPA in 2019, acknowledged as the the Most Ethical Multinational Company in 2019. The company continuously develops its four sites in Budapest, Debrecen, Pécs and Szeged and is looking for skilled IT professionals to join its team.

Job Description

The Project: Internal Support Tools Evolution  

You are joining an initiative focused on the evolution, modernization of the Internal Application Landscape. This project involves the strategic transition of well-known cloud services and legacy .NET architectures into a next-generation, AI-augmented, and cloud-native software landscape. 

Our goal is not simply to "maintain" the existing system, but to proactively transform it—ensuring sovereignty, high-performance scalability, and seamless handover readiness through disciplined engineering. 

Our Engineering Philosophy 

We operate at the intersection of Legacy Stability and Modern Innovation. Our approach is defined by: 

• AI-Augmented Engineering: We utilize advanced AI development environments (such as Cursor, Windsurf, and Claude Code) and cutting-edge model families to accelerate code comprehension, refactoring, and documentation. 

• Disciplined SDLC Patterns: We move beyond traditional development by implementing repeatable, evidence-based SDLC patterns. Every change is backed by structured engineering evidence and rigorous automated testing. 

• The "Strangler Fig" Modernization: We prioritize risk-mitigated evolution, using sophisticated patterns to wrap, refactor, and eventually replace legacy components. 

• High-Seniority Autonomy: We operate as a lean, highly autonomous unit. We value "technical detectives" who can navigate ambiguity and perform deep reverse engineering. 

Mission

To spearhead the technical evolution of our core enterprise ecosystem through a sophisticated Modernization Strategy. You will design the architectural patterns required to transition from legacy monolithic patterns to modern, scalable, AI-integrated architectures, ensuring zero downtime and seamless business continuity. 

Role Focus

This is a high-impact role at the intersection of legacy stability and modern innovation. You will lead the "Strangler Fig" approach—identifying components to wrap, refactor, or replace—while designing the architectural patterns for AI/LLM orchestration (e.g., API-driven AI orchestration, vector database integration) within the ecosystem. 

Key Responsibilities 

• Architectural Strategy & Roadmap: Design the long-term technical roadmap for the transition from legacy patterns to modern, scalable architectures (Microservices, Event-Driven, Cloud-Native). 

• Modernization Oversight: Lead the technical "archeology" of the legacy codebase, extracting complex, undocumented business logic and transforming it into clean, testable code. 

• AI Integration Architecture: Design the patterns required to integrate AI/LLM capabilities (e.g., agentic workflows, RAG pipelines) into the existing and future ecosystem. 

• Technical Decision Governance: Act as the final authority on architectural patterns, technology stacks, and coding standards to ensure consistency across the engineering team. 

• Technical Debt Management: Proactively identify, quantify, and prioritize technical debt, balancing rapid feature delivery with long-term system health. 

• Mentorship & Leadership: Provide high-level guidance to Senior and Mid-level developers, conducting deep-dive code reviews and fostering a culture of technical excellence. 

Qualifications

• Experience: 10+ years in software engineering, with at least 3+ years in a Lead Architect or Principal Engineer capacity. 

• Deep Technical Mastery: Expert knowledge of the .NET ecosystem (C#, .NET Core/6/8+, ASP.NET) and deep understanding of legacy .NET Framework internals. 

• Proven Migration Track Record: Demonstrated experience in successfully migrating or modernizing large-scale, complex legacy systems. 

• AI-Augmented Engineering: Proficiency in using AI tools (GitHub Copilot, LLMs) for code analysis, refactoring, and architectural prototyping. 

• Leadership: Ability to defend architectural decisions to stakeholders while earning the respect of high-seniority engineers. 

Additional Information

* Please be informed that our remote working possibility is only available within Hungary due to European taxation regulation.