Senior Backend Engineer (.NET) - Hybrid

About the role

Colliers, a global real estate advisory and investment management company, is looking for a Senior Backend Engineer for its newly established Technology Hub in Madrid. Reporting to the Director of Software Engineering, the engineer works in a hybrid model (remote and onsite) and joins the founding team that shapes the hub's culture, practices and technical direction. The role is focused on .NET and contributes to global products serving commercial real estate across multiple regions.

Key responsibilities

• Design, develop and maintain scalable, secure, high-performance B2B software using the Microsoft .NET stack (C#, ASP.NET Core)
• Take part in architecture discussions, technology evaluation, and system and code reviews, and help define coding standards and best practices such as SOLID, unit testing, CI/CD and secure coding
• Translate business requirements into technical specifications and user stories with product managers, designers and QA, and take part in sprint planning and backlog refinement
• Mentor mid-level and junior engineers, identify technical improvements and take ownership of production systems
• Promote test-first development with unit, integration and performance testing, support root cause analysis of production issues and contribute to platform refactoring
• Work with DevOps and Engineering Operations to optimise build pipelines, observability and deployment automation, and ensure compliance with global standards, information security and regulatory requirements

Required profile

• 8+ years of experience in .NET software development with C# and ASP.NET Core
• Strong object-oriented design, microservices and API development (REST/GraphQL)
• SQL and NoSQL databases (e.g. SQL Server, PostgreSQL, Cosmos DB, MongoDB) and caching with Redis or similar
• Cloud-native architectures, CI/CD and DevOps (preferably GCP), containerization (Docker, Kubernetes) and Agile (Scrum/Kanban)
• Distributed or remote team experience with Jira, GitHub, Miro and Azure DevOps
• Fluent English and Spanish

Preferred skills

• Domain-driven design and event-driven architecture
• Observability tools (e.g. Sentry, Lighthouse)
• Experience in a global, multi-cultural organisation