Lead .NET Architect (m/f/d) System Modernization & AI Integration

Job ID: 744000150089709

Lead .NET Architect (m/f/d) System Modernization & AI Integration

Pécs, Budapest, Debrecen

Professional

Regular

Deutsche Telekom ITTC Hungary Kft.

Your Task

You are joining an initiative focused on the evolution and 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. The 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.

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.

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.

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.

Your Profile

We are seeking a highly experienced Lead Architect or Principal Engineer with deep expertise in .NET ecosystem modernization, legacy system migration, and AI-augmented engineering. The ideal candidate will have proven experience in leading large-scale architectural transformations and possess strong leadership capabilities to guide high-seniority engineering teams.

Must Have Skills

• 10+ years of experience in software engineering
• At least 3+ years of experience in a Lead Architect or Principal Engineer capacity
• Expert knowledge of the .NET ecosystem (C#, .NET Core/6/8+, ASP.NET)
• Deep understanding of legacy .NET Framework internals
• Demonstrated experience in successfully migrating or modernizing large-scale, complex legacy systems
• Proficiency in using AI tools (GitHub Copilot, LLMs) for code analysis, refactoring, and architectural prototyping
• Ability to defend architectural decisions to stakeholders
• Ability to earn the respect of high-seniority engineers
• Experience with Microservices architecture
• Experience with Event-Driven architecture
• Experience with Cloud-Native architectures
• Knowledge of "Strangler Fig" modernization patterns
• Experience with AI/LLM integration and orchestration
• Experience with agentic workflows and RAG pipelines
• Experience with vector database integration
• Strong technical leadership and mentorship capabilities
• Experience with technical debt management and prioritization
• Proficiency with advanced AI development environments (such as Cursor, Windsurf, and Claude Code)
• Experience with disciplined SDLC patterns and automated testing
• Ability to navigate ambiguity and perform deep reverse engineering

About Us

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 received the Best in Educational Cooperation award from HIPA in 2019, acknowledged as 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.

Company Policies

• Remote working possibility is only available within Hungary due to European taxation regulation

Job Benefits

Work-Life Balance

Remote working possibility available within Hungary

Professional Development

• AI-Augmented Engineering tools (Cursor, Windsurf, Claude Code)
• Mentorship & Leadership opportunities