Mainframe developer Jobs in North York, ON

Our client, is seeking a deeply experienced, senior-level Mainframe Developer V to support a mission-critical transaction and client-data management platform within their merchant solutions division.

In this advanced technical role, you will act as a core engineering authority responsible for the end-to-end software development lifecycle (SDLC) of high-performance, secure, and scalable host-based software solutions. You will translate complex business rules into comprehensive technical design documents, engineer robust batch and online transaction processing programs, and oversee validation through unit, system, and integration testing phases. This role demands a strong engineering background in modern mainframe operating systems, relational data structures, and service-enabled integration patterns to maintain platform stability and meet stringent regulatory compliance frameworks.

Duration: 12-Month Contract (Extension possible based on performance and project pipeline)

Schedule: Monday – Friday, 9:00 AM – 5:00 PM (37.5 hours/week)

Work Arrangement: Hybrid (2 days per week on-site at the corporate office on Mondays and Wednesdays).



Advantages
Tier-1 Financial Footprint: Take ownership of core architecture driving high-volume merchant processing and consumer database systems for a major international banking infrastructure.

Long-Term Enterprise Mandate: Secure a stable 12-month contract assignment with active pathways for multi-quarter project extensions.

Modern Integration Scope: Work on an enterprise architecture that balances legacy stability with modern connectivity protocols, including service-enabled integrations and data file transfers.

Comprehensive Onboarding & Culture: Collaborate within an elite internal technology network that emphasizes engineering governance, technical documentation excellence, and operational transparency.



Responsibilities
Application Design, Development & Integration
Technical Solutioning: Analyze and translate abstract business requirements into high-fidelity technical design documents, blueprint models, and program specifications.

Mainframe Coding & Compilation: Design, code, extend, and debug high-performance mainframe application components leveraging COBOL, JCL, CICS, VSAM, and SAS.

Integration & File Transfer Engineering: Manage secure data ingestion and distribution pipelines using automated batch processing frameworks, TIBCO messaging, Network Data Mover (NDM), and structured FTP scripts.

Source & Configuration Control: Oversee application builds and release migrations using enterprise source control tools like Endevor, ensuring compliance with strict code-delivery guidelines.

Testing, Incident Management & Optimization
Full-Cycle Quality Assurance: Execute meticulous developer unit testing, support System Integration Testing (SIT), and facilitate smooth production implementations, including post-deployment stabilization activities.

Production Incident Diagnostics: Provide tier-3 technical support during critical runtime events and outages. Conduct systematic root-cause analysis, execute impact assessments, and communicate resolutions clearly with technology and business stakeholders. Note: Participation in a standard team on-call rotation may be required.

Infrastructure Capacity Tuning: Analyze database calls, job streams, and scheduling parameters via CA-7 to optimize computing performance, reduce processing overhead, and resolve systemic inefficiencies.

Governance & Remediation: Implement remediation steps to address audit, security compliance, data privacy, and architecture risk issues while handling sensitive backend customer master files safely.



Qualifications
Experience: Minimum 10+ years of progressive professional experience operating as a Senior Mainframe Developer, Software Engineer, or Application Architect within large-scale corporate data environments.

Core Mainframe Programming Mastery: Direct, expert-level hands-on experience designing and coding components using COBOL, JCL, CICS, VSAM, and SAS batch processing frameworks.

Technical Environment Fluency: Deep familiarity with host toolsets and ecosystems, specifically including IBM OS/390, Z/OS, TSO, ISPF, File-Aid, CA-7 scheduler, Endevor, and test script datasets.

Operational Ticketing System Literacy: Practical experience leveraging enterprise workflow tools like ServiceNow for incident, defect, and change management logs.

Education: Undergraduate degree, Postgraduate degree, or equivalent Technical Certification in Computer Science, Software Engineering, or a related quantitative engineering field.

Soft Skills: Outstanding analytical, problem-solving, and communication skills (written and verbal). A collaborative team player who can independently write complex system documentation and articulate abstract technical concepts easily to internal multi-disciplinary squads.

Nice-to-Have Skills & Assets
Prior professional software engineering experience working within the Financial Services, Banking, or Card Payment Network industries.



Summary
If you are a veteran Mainframe Developer V who pairs a deep 10+ year mastery of COBOL, JCL, and CICS with the analytical precision required to draft software design specifications and handle complex data lake integrations, this 12-month hybrid contract is an exceptional career platform. Bring your architectural discipline, batch tuning skills, and proactive team mindset to an industry-defining merchant solutions engineering group today!

Randstad Canada is committed to fostering a workforce reflective of all peoples of Canada. As a result, we are committed to developing and implementing strategies to increase the equity, diversity and inclusion within the workplace by examining our internal policies, practices, and systems throughout the entire lifecycle of our workforce, including its recruitment, retention and advancement for all employees. In addition to our deep commitment to respecting human rights, we are dedicated to positive actions to affect change to ensure everyone has full participation in the workforce free from any barriers, systemic or otherwise, especially equity-seeking groups who are usually underrepresented in Canada's workforce, including those who identify as women or non-binary/gender non-conforming; Indigenous or Aboriginal Peoples; persons with disabilities (visible or invisible) and; members of visible minorities, racialized groups and the LGBTQ2+ community.

Randstad Canada is committed to creating and maintaining an inclusive and accessible workplace for all its candidates and employees by supporting their accessibility and accommodation needs throughout the employment lifecycle. We ask that all job applications please identify any accommodation requirements by sending an email to accessibility@randstad.ca to ensure their ability to fully participate in the interview process.