Sr Software Engineer

Work Schedule Standard (Mon-Fri) Environmental Conditions Office Job Description As part of the Thermo Fisher Scientific team, you’ll discover meaningful work that makes a positive impact on a global scale. Join our colleagues in bringing our Mission to life every single day to enable our customers to make the world healthier, cleaner and safer. We provide our global teams with the resources needed to achieve individual career goals while helping to take science a step beyond by developing solutions for some of the world’s toughest challenges, like protecting the environment, making sure our food is safe or helping find cures for cancer. DESCRIPTION: Position Summary We are seeking a Senior Mainframe Developer to design, develop, and support critical enterprise applications in a complex mainframe environment. This role requires deep technical expertise in COBOL-based systems, strong problem-solving skills, and the ability to contribute to modernization initiatives, including API enablement and integration with distributed platforms. This individual will play a key role in ensuring system reliability, driving technical improvements, and partnering with cross-functional teams to deliver high-quality solutions. Key Responsibilities Design, develop, test, and maintain applications using COBOL, CICS, VSAM, and IDMS Analyze business requirements and translate them into scalable, maintainable technical solutions Support and enhance legacy systems while contributing to modernization and transformation efforts Develop and expose APIs and services to enable integration between mainframe and distributed systems Participate in production support, including root cause analysis and issue resolution Provide on-call support, including weekends and off-hours, as part of a rotation Collaborate with Product Managers, Business Analysts, QA, and other engineering teams Lead or contribute to code reviews, technical design sessions, and best practice development Identify opportunities for process improvement, automation, and performance optimization Mentor junior developers and provide technical guidance across the team Ensure adherence to security, compliance, and development standards Required Qualifications 7+ years of experience in mainframe application development Strong hands-on experience with: COBOL CICS VSAM IDMS Easytrieve Experience with batch and online processing environments Proven experience supporting mission-critical production systems Strong debugging, analytical, and problem-solving skills Experience working in Agile or Scrum environments Excellent communication skills, with the ability to work across technical and business teams Willingness to participate in on-call rotation (weekends and off-hours) Preferred Qualifications Experience with mainframe modernization initiatives API enablement (e.g., REST services, z/OS Connect, etc.) Integration with cloud or distributed platforms Familiarity with DevOps practices and CI/CD pipelines in a mainframe context Experience with performance tuning and system optimization Exposure to tools such as Endevor, Changeman, or similar Experience working in hybrid environments (mainframe + distributed systems) Work Environment Hybrid work model: Onsite at least 3 days per week Participation in an on-call rotation, including weekends and off-hours support What Success Looks Like Delivers high-quality, reliable code in a complex legacy environment Drives incremental modernization while maintaining system stability Acts as a technical leader and trusted partner to stakeholders Improves team velocity through better design, automation, and collaboration