Architect / Lead Software Developer

On behalf of our client from Ireland, Mobilunity is looking for a Architect / Lead Software
Developer (PHP to .Net Migration).
Our client is an indirect tax technology company that provides software and services for VAT
compliance, VAT recovery, eInvoicing, and cross-border payments for global businesses. It is a
mature B2B fintech company with strong enterprise traction, a large client base, and a recent
rebrand aimed at broadening its identity beyond VAT recovery.
The client operates a large-scale backend platform used for transactional and operational
workflows. The system is a mature PHP/Laravel-based solution with significant business logic
accumulated over time and limited test coverage. The company is now planning a strategic
migration to a modern .NET (C#) architecture to improve scalability, maintainability, and long-
term engineering velocity.
The engineering team is highly technical and well-structured, with clear ownership and a strong
focus on system reliability and the controlled evolution of the platform.
About the role
They are looking for a Senior Software Architect to lead the assessment and migration of a
large-scale legacy PHP/Laravel system into a modern .NET (C#) architecture. The role starts
with a deep technical discovery phase, where you will analyze the existing system, define the
target architecture, and design a clear migration strategy. Following this, you will lead the
execution phase and guide a small engineering team through phased system transformation.
You will be responsible for both high-level architecture decisions and hands-on technical
guidance, ensuring a safe, structured, and incremental migration of critical business
functionality.

Key Responsibilities:

• Analyzing and reverse-engineering a large PHP/Laravel monolith (~enterprise-scale system)
• Identifying core business logic, dependencies, and third-party components
• Designing target .NET (C#) architecture and system structure
• Defining migration strategy (incremental vs full rewrite approach)
• Creating technical roadmap and effort estimation
• Leading and supporting backend engineers during implementation phase
• Ensuring system stability during parallel run and transition period
• Collaborating closely with client-side engineering team on validation and delivery

Must-have skills:

• Strong experience with PHP (Laravel) and .NET (C#) in production systems
• Proven background in large-scale system modernization or cross-platform migration
• Strong software architecture and system design skills
• Experience working with complex legacy codebases
• Ability to decompose monolithic systems into modular architecture
• Experience defining technical roadmaps and migration strategies
• Strong communication skills and ability to work in close collaboration with client teams
• Leadership experience in guiding engineers through complex technical transformations
• Fluent English

In return we offer:

• The friendliest community of like-minded IT-people
• Open knowledge-sharing environment – exclusive access to a rich pool of colleagues willing
to share their endless insights into the broadest variety of modern technologies
• Mobilunity Medical Insurance program designed to attend our teams’ needs
• Paid vacations and sick leaves, including 5 paid days per year that don’t require a sick note
• Perfect office location in the city-center (900m from Lukyanivska metro station with a green
and spacious neighborhood) or remote mode engagement: you can choose a convenient one
for you, with a possibility to fit together both
• No open-spaces setup – separate rooms for every team’s comfort and multiple lounge and
gaming zones
• English classes in 1-to-1 & group modes with elements of gamification
• Neverending fun: sports events, tournaments, music band, multiple affinity groups
COME ON BOARD, AND LET’S GROW TOGETHER!