Junior Mainframe Developer, Summer 2026 (Co-op / Internship) - 4 months

Application Deadline :

02 / 22 / 2026

Address :

33 Dundas Street West

Job Family Group : Technology

As a co-op / intern student at BMO, you will have the opportunity to be heard, keep growing and make a difference.

You will be part of our campus program to gain the skills and knowledge needed to take on roles similar to the description listed below.

Our student experience is designed to integrate you to the BMO team from day one by adding value in the work you do. You will have the opportunity to participate in programs such as the Women in Technology Mentorship Program, BMO Social Squad student-led activities, BMO Academy corporate learning platform, and access to various Employee Resource Groups to further develop your network within BMO.

Interested in learning more about our campus program? Stay up-to-date with BMO Campus Recruitment by following us on Instagram @BMO_on_Campus and joining our LinkedIn group BMO Campus Recruiting & Early Talent.

Note : Only students currently enrolled in an academic program and returning to their studies will be considered for Co-op / Internship opportunities. Student who recently graduated are invited to apply to our New Grad opportunities which are available at

To apply for this opportunity, please submit your cover letter, resume and an unofficial copy of your academic transcript. By applying for this general posting, you will be considered for a number of different student opportunities across multiple locations. If you are selected to move forward, you will be provided additional information.

Join BMO’s Everyday Banking (EDB) Platform team to learn about how mainframes run the BMO’s core banking business. Along with gaining skills in mainframe coding basics, you will learn about the systems involved in transactions you use on a daily basis, while building your personal and professional network.

Drives the overall software development lifecycle including working across functional teams to transform requirements into features, managing development teams and processes, and conducting software testing and maintenance. Specific project areas of focus includes translating user requirements into technical specifications, writing code and managing the preparation of design specifications. Supports system design, provides advice on security requirements and debugs business systems and service applications. Applies deep knowledge of algorithms, data structures and programming languages to develop high quality technology applications and services - including tools, standards, and relevant software platforms based on business requirements.

• Translates user needs into technical specifications by understanding, conceptualizing, and facilitating technical requirements from user.​
• Analyzes, develops, tests, and implements new software programs, and documentation of entire software development life cycle execution.
• Performs preventative and corrective maintenance, troubleshooting and fault rectification of system and core software components​.
• Ensures that code / configurations adhere to the security, logging, error handling, and performance standards and non-functional requirements.​
• Evaluates new technologies for fit with the program / system / eco-system and the associated upstream and downstream impacts on process, data, and risk.
• Follows release management processes and standards, and applies version controls. ​
• Assists in interpreting and documentation of client requirements.​
• Focus may be on a business / group.
• Thinks creatively and proposes new solutions.
• Exercises judgment to identify, diagnose, and solve problems within given rules.
• Works mostly independently.
• Broader work or accountabilities may be assigned as needed.

Qualifications :

Foundational level of proficiency :

Salary :

$50,100.00 - $93,000.00

Pay Type : Salaried

The above represents BMO Financial Group’s pay range and type.

Salaries will vary based on factors such as location, skills, experience, education, and qualifications for the role, and may include a commission structure. Salaries for part-time roles will be pro-rated based on number of hours regularly worked. For commission roles, the salary listed above represents BMO Financial Group’s expected target for the first year in this position.

BMO Financial Group’s total compensation package will vary based on the pay type of the position and may include performance-based incentives, discretionary bonuses, as well as other perks and rewards. BMO also offers health insurance, tuition reimbursement, accident and life insurance, and retirement savings plans. To view more details of our benefits, please visit :

About Us

At BMO we are driven by a shared Purpose : Boldly Grow the Good in business and life. It calls on us to create lasting, positive change for our customers, our communities and our people. By working together, innovating and pushing boundaries, we transform lives and businesses, and power economic growth around the world.

As a member of the BMO team you are valued, respected and heard, and you have more ways to grow and make an impact. We strive to help you make an impact from day one – for yourself and our customers. We’ll support you with the tools and resources you need to reach new milestones, as you help our customers reach theirs. From in-depth training and coaching, to manager support and network-building opportunities, we’ll help you gain valuable experience, and broaden your skillset.

To find out more visit us at .

BMO is committed to an inclusive, equitable and accessible workplace. By learning from each other’s differences, we gain strength through our people and our perspectives. Accommodations are available on request for candidates taking part in all aspects of the selection process. To request accommodation, please contact your recruiter.

Note to Recruiters : BMO does not accept unsolicited resumes from any source other than directly from a candidate. Any unsolicited resumes sent to BMO, directly or indirectly, will be considered BMO property. BMO will not pay a fee for any placement resulting from the receipt of an unsolicited resume. A recruiting agency must first have a valid, written and fully executed agency agreement contract for service to submit resumes.