Principal Software Engineer

Job Title: Principal, Software Development Engineer Location: Toronto, ON Duration: Full time Permanent role About The Role As a Principal Software Development Engineer on the AI Model Serving team, you will be a technical leader who helps shape the vision and direction of the platform alongside the engineering manager. You will play a central role in making critical design decisions, driving outcomes across the team, and setting a positive and inclusive team culture. In addition to the model serving platform, the team also owns the production model registry at Client, and you will help guide its evolution and ensure it meets the needs of ML teams across the organization. Your work will directly impact Client’s ability to serve AI at scale — from traditional ML models to the latest large language models powering Client’s agents. Key Responsibilities: Help set the product vision for the AI Model Serving platform in partnership with the engineering manager, bringing a product-oriented mindset to infrastructure decisions. Lead the team technically by making critical design decisions that drive performance, reliability, and scalability across the platform. Design, implement, and maintain large-scale systems that enable moving ML models to production. Write design documents to build consensus for new system components and enhancements to existing components. Evaluate and uptake new technologies made available within Workday and across the broader industry. Troubleshoot, improve, and scale continuous integration software pipelines. Develop relationships with software engineers, machine learning engineers, and data scientists on partner teams. Respond to alerts and debug production issues to maintain platform health and reliability. Review pull requests and enforce consistency, performance, readability, and security across code bases. Develop documentation to share knowledge with other engineers. About You Basic Qualifications 8+ years of related work experience in software development, with a focus on building and operating large-scale distributed systems. Bachelor's degree in Computer Science, Engineering, or a related technical field (or equivalent practical experience). Other Qualifications Software Development and Distributed Systems: Deep experience designing, building, and scaling production-grade distributed systems. You understand the full software development lifecycle — from coding standards and testing to code reviews, source control management, and deployment — and you can apply that knowledge to complex, high-throughput platforms. Python: Deep proficiency in Python, with extensive experience writing production-level code and building systems in Python-based frameworks. LLMs and Traditional ML Models: Familiarity with both large language models and traditional machine learning models, including how they are served, scaled, and monitored in production environments. You understand the operational differences and can design platform abstractions that serve both effectively. You can design and maintain monitoring strategies that provide clear insight into system health, performance, and cost. Excellent written and verbal communication skills, including the ability to write clear design documents, articulate complex technical ideas, and build consensus across teams. A collaborative approach to engineering, with experience mentoring other engineers and fostering an inclusive team environment.

Lead the technical vision and design of the AI Model Serving platform and production model registry. Drive the implementation of scalable systems to move ML models into production while mentoring engineers and collaborating with cross-functional teams.

Requires 8+ years of experience in software development with a focus on large-scale distributed systems and deep proficiency in Python. Candidates should have familiarity with serving and monitoring both traditional ML and large language models.

Identified from the job description. Confirm important requirements above.

• Distributed Systems
• Python
• Large Language Models
• Machine Learning
• System Design
• CI/CD Pipelines
• Model Serving
• Scalability
• Production Monitoring
• Technical Leadership
• API Design
• Software Development Lifecycle

Minimum education

Bachelor’s degree

Minimum experience

10+ years

Apply by

Aug 26, 2026