Senior Software Engineer — C# (.NET Core) | API Development

Standard (Mon-Fri) Environmental Conditions Office Job Description Experience Level: 6–9 Years Team: Data Governance and Analytics Organization: Data, AI, and Visualization (DAIV), Global Software R&D About the team

Our work prepares the organization for the age of AI, supports data-driven design, and enables value creation from data. About the role We are seeking a highly skilled Senior Software Engineer specializing in C# (.NET Core) and robust API Development . In this role, you will design, build, and scale high-performance backend microservices and secure, enterprise-grade RESTful APIs. You will work closely with cross-functional architecture, product, and platform teams to deliver scalable services that power our core product ecosystem and support seamless system integration.

About Thermofisher

• The Data Governance and Analytics Team is part of Data, AI, and Visualization (DAIV) within our global software R&D organization.
• We are a diverse, distributed team with colleagues across France and the Netherlands.
• We bring digital technology into our products, solutions, and services, enabling data extraction, analysis, and connectivity.
• We develop software that supports data governance by managing data definitions, improving data quality, and making data more usable and useful.

Responsibilities

• Design, development, and lifecycle management of scalable, secure, and well-documented RESTful APIs and microservices using C# and .NET Core .
• Design efficient data access layers, database schemas, and LINQ queries using Entity Framework , ensuring optimal performance, change tracking, and migration management.
• Design, develop, test, and maintain C# software libraries and reusable components supporting data extraction, analysis, connectivity, and governance.
• Translate functional and technical requirements into clear software designs and implementations.
• Develop components that support consistent data definitions, validation, and data quality.
• Identify opportunities to reuse existing software and reduce duplication across products and projects.
• Support the integration of libraries and components into applications and engineering workflows.
• Develop and maintain automated tests to validate functionality and prevent regressions.
• Contribute to build pipelines, test automation, and automated deployment using GitLab or GitHub.
• Apply secure development practices and support DevSecOps activities within the development lifecycle.
• Investigate defects, troubleshoot integration issues, and improve software reliability.
• Maintain technical documentation and clear runbooks covering component interfaces, configuration, integration dependencies, and usage.
• Collaborate with software architects and engineers across the wider R&D organization.
• Establish strong reliability practices (logging/monitoring, retries/backoff, idempotency, concurrency controls, safe cleanup, traceability).
• Mentor engineers through code reviews, best practices, and technical leadership.
• Work effectively within an Agile Scrum / SAFe framework , participating in backlog refinement, sprint planning, technical estimation, PI planning, reviews, retrospectives, and cross-team coordination to support predictable and high-quality delivery.

Requirements

• Skills Strong Working knowledge of C#, .NET Core and object-oriented software development with API development, Database experience.
• Experience integrating shared libraries or components across multiple applications.
• Experience with both relational and non-relational databases (e.g., MariaDB, MongoDB, PostgreSQL, SQL Server).
• Proven experience designing, building, versioning, and securing RESTful APIs at scale.
• Ability to develop and maintain modular, reusable software components.
• Understanding of software testing, debugging, and version-control practices.
• Experience working in an agile DevOps environment.
• Experience using GitLab or GitHub for source control and collaborative development.
• Familiarity with build pipelines, automated testing, and automated deployment.
• Understanding of containerization concepts, with familiarity with technologies such as Docker, K8s, Helm, etc Ability to collaborate effectively with colleagues in a distributed international team.
• Working knowledge of Agile delivery frameworks, including Scrum and SAFe, with experience operating effectively in sprint-based and cross-team planning environments.
• Strong communication and stakeholder management skills, with the ability to work effectively across global, cross-functional teams.
• Experience operating in structured product-development environments with strong quality, compliance, and delivery expectations Preferred Qualifications Bachelor’s or master’s degree, preferably in a technical or scientific discipline.
• 6+ years of software engineering experience with a strong focus on C# and .NET Core and object-oriented software development with API development, Database experience.