Full Stack Developer - HR Systems Integration

For our client, an international financial company, we are looking for: Full Stack Developer, HR Enterprise Systems Location: Warsaw, Poland (3 days in office per week) Salary: 28 000 – 38 000 PLN gross / month (employment) Tasks: Build and own integrations between enterprise systems and third-party HR SaaS platforms (70% backend, 30% frontend)Lead end-to-end technical delivery of integration projectsDesign and implement robust RESTful APIs and web service adapters that handle both modern REST and legacy SOAP interfacesPartner with HR, Talent Acquisition, Finance and other corporate teams to gather and manager requirementsAct as the cloud-native integration owner with security and compliance teamsImplement and maintain CI/CD pipelines, automated tests and monitoring Requirements: 5+ years of experience in software engineering (development & design)Hands-on experience in SaaS HR software integration (preferably in-house)Knowledge of one of major backend languages and also JavaScript or TypeScript (preferred stack: Java, Python, JS)Proven experience designing and implementing RESTful APIs and integrating third-party web servicesExperience with authentication and authorization standards (OAuth2, OIDC, SAML and SSO)Experience building and operating services on a major cloud platform (AWS preferred)Experience with Git, CI/CD and IaC (Terraform)Some experience with frontend developmentSome experience in gathering and managing requirements (liaising with stakeholders)Fluent in English