Senior Integration Engineer – C#/.NET & HR Systems (Hybrid, Warsaw)

We are looking for a Senior Integration Engineer - HR Systems to design, build and operate integrations connecting HR platforms, enterprise applications and third-party SaaS solutions.

Hands-on experience integrating HRIS, HCM or other HR technology platforms is a key requirement. You’ll own integration projects end-to-end, from requirements and solution design through development, deployment and ongoing production support.

What you’ll do:

• Design, develop and maintain production-grade integrations between HR systems, enterprise applications and SaaS platforms.
• Build robust APIs and web service integrations using REST and SOAP.
• Work with HR, Talent Acquisition, Finance and other business stakeholders to understand processes, gather requirements and translate them into scalable technical solutions.
• Support the secure exchange of employee and corporate data across multiple systems and platforms.
• Implement authentication, authorisation and security controls using OAuth2, OIDC, SAML, SSO, Active Directory and LDAP.
• Develop and operate cloud-based integration services using AWS and Terraform, including relevant networking and security configuration.
• Build and maintain CI/CD pipelines, automated testing, monitoring and observability.
• Troubleshoot production integrations, analyse logs, investigate root causes and drive improvements to system reliability.
• Establish reusable integration patterns, technical standards and documentation, while sharing knowledge with other engineers.

What we’re looking for:

• 5–7+ years’ professional software engineering experience, including ownership of enterprise integrations in production.
• Hands-on experience integrating HRIS, HCM or other HR technology products/platforms.
• Strong backend engineering skills in one or more of Java, C#/.NET, Python, Node.js or Go.
• Proven experience designing and implementing REST APIs and integrating third-party web services, including SOAP.
• Practical experience with OAuth2, OIDC, SAML, SSO, Active Directory and LDAP.
• Experience building and operating services on AWS and using Terraform or similar infrastructure-as-code tools.
• Strong knowledge of Git, CI/CD, automated testing, monitoring and production support.
• Solid SQL and relational database experience.
• Experience working with enterprise SaaS integrations and complex cross-system data flows.
• Working knowledge of HTML, CSS and JavaScript or a modern frontend framework.
• Strong stakeholder management skills, with the ability to gather requirements, understand business processes, explain technical trade-offs and work effectively with security and compliance teams.
• Excellent written and verbal English communication skills.

If you’re an experienced integration engineer with a background in HR technology and enterprise SaaS integrations, and enjoy owning complex solutions from design through production, we’d be interested in hearing from you.