Senior Software Engineer, Applied AI (Toronto)

Justworks is a cloud-based software platform that helps businesses manage HR, payroll, benefits, and compliance. The company is building a world where starting and running a growing business is accessible.

We are seeking a Senior Software Engineer to join a small, autonomous cross-functional team building AI agents that transform operations at scale. The team is developing an agent platform that reads operational knowledge, reasons about it, and executes tasks end-to-end. This is a foundational team of fewer than five engineers.

• Design, build, and own core components of the agent platform, from orchestration to tool integrations.
• Build the capabilities layer: APIs, data access patterns, and service integrations for agents.
• Architect knowledge and memory infrastructure for agent retrieval and action.
• Design trust and safety framework including audit trails, human-in-the-loop controls, and guardrails.
• Contribute to agent evaluation and testing infrastructure.
• Partner with Operations to identify automation opportunities.
• Mentor other engineers as the team grows.

• 5+ years of backend engineering experience building and operating production systems.
• Hands-on experience with LLMs and AI agents (orchestration, RAG, tool/function calling).
• Strong API design and system integration skills.
• Product-minded with a focus on practical solutions.
• Proven ownership of complex projects in ambiguous environments.

Golang, Ruby on Rails, JavaScript, Java, C#, Python, VueJS, MySQL, Kafka, AWS, Git, Memcache, Redis, ElasticSearch, Docker, Terraform, Kubernetes, CircleCI, DataDog.

Base wage range for Toronto office: $188,000 - $242,000 CAD per year.

Justworks offers a welcoming environment, wellness program offerings, and company retreats. For full details, see Total Rewards @ Justworks.