We are looking for a seasoned " Mainframe Developer" with strong expertise in IBM DB2 and other core mainframe technologies. The ideal candidate will be responsible for designing, developing, and maintaining high-performance, scalable mainframe applications. Full-time role with Ascendion 3 days onsite in Chester, UK Design, develop, test, and maintain applications on mainframe systems using COBOL, IMS, z/OS. Work with IBM DB2 for data management and optimization. Troubleshoot and resolve production issues promptly. About us - Ascendion is a global, leading provider of AI-first software engineering services, delivering transformative solutions across North America, APAC, and Europe. We are headquartered in New Jersey. We combine technology and talent to deliver tech debt relief, improve engineering productivity solutions, and accelerate time to value, driving our clients’ digital journeys with efficiency and velocity. Guided by our “Engineering to the power of AI” [EngineeringAI] methodology, we integrate AI into software engineering, enterprise operations, and talent orchestration, to address critical challenges of trust, speed, and capital.