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Senior Mainframe Developer Jobs in Whitby, ON (NOW HIRING)

The Senior Mainframe Developer is responsible for the design, development, modernization, and support of critical applications within Core Investment Management (Core IM). The role involves ...

New

As a Senior Developer, you will be working in a development and support capacity on our core mainframe cards and transactions system. The core application is a large, sophisticated mainframe-based ...

Senior Software Engineer (Mainframe)

Toronto, ON · On-site

CA$81K - CA$115K/yr

Adhere to enterprise engineering frameworks, software development methodologies, release processes, and control standards applicable to mainframe development and delivery. * Actively identify and ...

The ideal candidate will have a proven track record of leading large-scale mainframe and ... Promote automation, CI/CD pipelines, DevOps practices, and agile methodologies. * Continuously ...

Canadian Banking Engineering is looking for a senior Solution Architect to enable enterprise scale ... mainframe, transactional systems) and modern technologies (microservices, REST APIs, cloud ...

As a Senior Project Manager, you willbe responsible foroverseeing project planning, execution,and ... Science, Engineering or similar). * Experience managing or working on mainframe software ...

Contributes to the overall success of Client Management & Engagement Engineering ensuring specific ... Mainframe environment Experience with testing large data transformations and migrations at ...

... DevOps for deployment, and Git repositories. Understanding and experience with Spring Framework ... have: mainframe development experience and enterprise architectural knowledge/experience ...

Partner with vendors, solution designers, and engineers to align on design, API behaviours, data ... Knowledge of mainframe integration patterns, including batch processing and flat file exchanges.

Provide program-level updates and insights to senior technology and business leaders, ensuring ... REST APIs, Mainframe technologies, Windows/SQL Server, Java, Apache Tomcat, Salesforce, GitHub ...

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Senior Mainframe Developer information

What is a senior mainframe developer?

Senior Mainframe Developers are experienced professionals who design, develop, and maintain mainframe systems—large-scale computers used by organizations for critical applications, bulk data processing, and enterprise resource planning. They are proficient in languages like COBOL, JCL, and Assembler, and often work with databases and transaction processing systems. Their responsibilities include troubleshooting system issues, optimizing performance, mentoring junior developers, and ensuring the reliability and security of mainframe operations.

What are some common challenges faced by senior mainframe developers when integrating legacy systems with modern technologies?

Senior Mainframe Developers often encounter challenges when integrating legacy mainframe systems with newer technologies such as cloud platforms, APIs, or microservices. These challenges include ensuring data consistency, maintaining system security, and minimizing downtime during migrations. Collaboration with cross-functional teams, such as infrastructure engineers and application developers, is key to developing seamless integration solutions. Staying up-to-date with modernization tools and best practices can help address these complexities and support the organization's digital transformation goals.

What are the key skills and qualifications needed to thrive as a senior mainframe developer, and why are they important?

To thrive as a Senior Mainframe Developer, you need deep expertise in mainframe programming languages (like COBOL, JCL, and PL/I), systems analysis, and a strong understanding of legacy application architectures, typically supported by a degree in computer science or related experience. Familiarity with tools such as IBM z/OS, DB2, CICS, and version control systems is essential, along with relevant certifications like IBM Certified System Programmer. Excellent problem-solving, communication, and leadership skills help you collaborate effectively and mentor junior developers. These skills are crucial for maintaining mission-critical systems, ensuring reliability, and guiding modernization efforts in complex enterprise environments.

What cities near Whitby, ON are hiring for Senior Mainframe Developer jobs?

Cities near Whitby, ON with the most Senior Mainframe Developer job openings:

Infographic showing various Senior Mainframe Developer job openings in Whitby, ON as of August 2026, with employment types broken down into 79% Full Time, 3% Part Time, and 18% Contract. Highlights an 80% Physical, 6% Hybrid, and 14% Remote job distribution.

Senior Mainframe Developer - Application Design - Hybrid

Tech Talent International

Toronto, ON • Hybrid

CA$50/hr

Full-time

Re-posted 4 days ago


Job description

Tech Talent International (TTI) supplies technical talent to a variety of clients ranging from Fortune 100/500/1000 companies to startups, small and mid-sized organizations in Canada/US. We are currently hiring a Senior Mainframe Developer - Application Design - Hybrid for our consulting client in the Toronto area.

Role: Senior Mainframe Developer - Application Design - Hybrid

Type: Contract

Rate Range: $50/hr C2C (40 hrs /week)

Duration: 8 months + potential extensions

Location: Hybrid (2 onsite/3 days from home) downtown Toronto, ON, Canada

Mainframe Senior Developer
Skills Required: 

Mainframe DB2 

Application Development~System I 

COBOL400~IT IS_AMS_Mainframe_DB2 Administration
Experience Required: 6-8 Years
Qualifications :

Experience in Mainframe lead Developer
Should have coding experience in CICS,COBOL, DB2, JCL.
Experience with application design, development and deployment
Skills and Responsibilities:

Design, develop and maintain Mainframe COBOL & JCL to meet support and/or project requirements.
Interface with business and IT teams to understand business requirements and translate business requirements into formal technical requirements and application code.
Develop and execute unit test and integration plans/scripts to validate that application changes meet technical specifications.
Responsible for full System Development Life Cycle Participate in production support Provide Solution Delivery Methodology artifacts associated with application components.
Participate in technical reviews at appropriate stages of development.