Tooling engineer Jobs in Milton, ON

About the Role

We are seeking a Senior Software Developer to design, build, and support mission‑critical enterprise software platforms used across large‑scale healthcare and pharmacy operations. This role is a senior individual contributor position with significant autonomy, technical ownership, and responsibility for system reliability, scalability, and performance.

You will work primarily on backend services, APIs, and integrations, contributing across both modern services and established enterprise applications. Success in this role requires comfort working in complex, highly regulated environments, collaborating cross‑functionally, and making sound technical decisions that consider operational risk and downstream impact.

This is a hybrid role, working 2 days per week in Mississauga or Montreal.

What You’ll Do:

• Design, develop, and maintain backend services, APIs, and enterprise system components using C# and .NET technologies
• Work across modern backend services as well as established .NET Framework applications, contributing to enhancements, remediation, and modernization
• Develop secure, scalable, and maintainable solutions supporting high‑volume transactional systems
• Collaborate with Product Owners and stakeholders to clarify requirements and translate business needs into technical solutions
• Participate in system and solution design discussions, recommending architectural and reliability improvements
• Write and maintain automated tests (unit, integration, service‑level)
• Contribute to CI/CD pipelines, Git‑based workflows, and deployment automation
• Support production systems, including troubleshooting, root‑cause analysis, and stability improvements
• Conduct peer code reviews and contribute to engineering standards and best practices
• Produce clear technical documentation (design notes, APIs, operational runbooks)
• Act as a technical resource and mentor for less‑experienced developers without formal people management

Basic Requirements:

• Bachelor’s degree in Computer Science, Engineering, or a related field OR equivalent combination of education and experience
• 7+ years of professional software development experience
• Strong hands‑on experience with C# and .NET / .NET Framework
• Experience building and supporting enterprise‑scale applications
• Proficiency with SQL Server and data access technologies (e.g., Entity Framework, Dapper)
• Experience working in large, complex organizations (Healthcare, Pharma, Manufacturing, Financial Services)
• Experience working in Agile/Scrum environments

Preferred Skills / Experience:

• Experience with ASP.NET Web API / MVC
• Exposure to .NET Core / .NET 6+
• Cloud experience (e.g., Azure or AWS)
• CI/CD tooling and DevOps practices
• Experience with legacy system modernization
• Front‑end exposure (React or Angular) to support end‑to‑end collaboration
• Experience working in regulated environments (healthcare, financial, or other compliance‑driven sectors)

We are proud to offer a competitive compensation package at McKesson as part of our Total Rewards. This is determined by several factors, including performance, experience and skills, equity, regular job market evaluations, and geographical markets. The pay range shown below is aligned with McKesson's pay philosophy, and pay will always be compliant with any applicable regulations. In addition to base pay, other compensation, such as an annual bonus or long-term incentive opportunities may be offered. For more information regarding benefits at McKesson, please

Our Base Pay Range for this position

$99,100 - $132,100

McKesson has become aware of online recruiting-related scams in which individuals who are not affiliated with or authorized by McKesson are using McKesson’s (or affiliated entities, like CoverMyMeds or RxCrossroads) name in fraudulent emails, job postings or social media messages. In light of these scams, please bear the following in mind:

McKesson Talent Advisors will never solicit money or credit card information in connection with a McKesson job application.

McKesson Talent Advisors do not communicate with candidates via online chatrooms or using email accounts such as Gmail or Hotmail. Note that McKesson does rely on a virtual assistant (Gia) for certain recruiting-related communications with candidates.

McKesson job postings are posted on our career site: .