Senior Backend Engineer (Hybrid)

• Implement scalable and maintainable B2B software products using the Microsoft .NET stack (C#, ASP.NET Core).
• Contribute to architecture discussions, technology evaluation and participate in system and code reviews.
• Define and adhere to coding standards, documentation and modern software lifecycle best practices such as SOLID principles, unit testing, CI/CD and secure coding.
• Collaborate with product managers, designers, and QA to translate business requirements into technical specifications and user stories.
• Participate in sprint planning, backlog refinement and feature grooming to ensure technical feasibility and shared understanding across disciplines.
• Act as a technical mentor to mid-level and junior engineers within and beyond your team.
• Identify opportunities for technical improvements and advocate for high-quality engineering standards.
• Take on technical ownership of production systems and support root cause analysis and resolution of production issues, ensuring high reliability and uptime.
• Drive a culture of test-first development with unit, integration and performance testing.
• Work closely with DevOps and Engineering Operations teams to optimize build pipelines, observability and deployment automation.
• Ensure compliance with global standards, information security policies and regulatory requirements.
• Collaborate regularly with Product Teams, especially Product Owners, to align on requirements, clarify priorities and deliver business value iteratively.

• 5+ years of experience in .NET software development with C# and ASP.NET Core.
• Strong knowledge of object-oriented design, microservices architecture and API development (REST/GraphQL).
• Experience with SQL and NoSQL databases (SQL Server, PostgreSQL, Cosmos DB, MongoDB) and caching with Redis.
• Advanced understanding of cloud-native architectures, CI/CD pipelines and DevOps practices (preferably GCP).
• Experience in containerization (Docker, Kubernetes).
• Agile development experience (Scrum/Kanban), including story estimation, code reviews and pair programming.
• Experience working in distributed or remote teams using tools such as Jira, GitHub, Miro and Azure DevOps.
• Solid understanding of performance optimization.
• Excellent interpersonal and communication skills, fluent in English and Spanish.
• Passionate about building high-quality software products with empowered teams.
• Understanding of secure development practices and compliance frameworks (ISO 27001, GDPR, SOC 2).

Preferred Skills

• Experience working in a global, multi-cultural organization.
• Exposure to domain-driven design and event-driven architecture.
• Experience with observability tools such as Sentry, Lighthouse, etc.
• Ability to work in a fast-paced, growing tech environment and foster change in larger organizations.

Colliers is a leading diversified professional services and investment management company operating in 68 countries with 22,000 employees who work collaboratively to maximize the potential of property and real assets. We are seeking an experienced and passionate Senior Backend Engineer for our Technology in Madrid. This unique opportunity allows you to join the founding team that helps shape our culture, practices and technical direction. Working in a hybrid model (remote and onsite), you will innovate and influence the future of one of the world's largest commercial real estate companies.