Senior Software Developer, LLM Infrastructure

Wealthsimple Technologies • ,

10d • CA$152,900 - CA$189,000 • Hybrid

About The Position

The Machine Learning Infrastructure team builds the core foundation powering AI and GenAI initiatives across Wealthsimple. As our AI footprint expands, our priority is building scalable, cost-effective infrastructure that enables high-performance inference using open-source models alongside vendor solutions. The Senior Software Engineer on the ML Infrastructure team will design and implement the core backend and infrastructure powering our AI systems. They will work closely with data scientists, platform engineers, and engineering leaders to scale our GenAI footprint efficiently and securely.

Requirements

• 6+ years of software engineering experience building production-ready distributed systems or data platform infrastructure.
• Strong proficiency in Python and infrastructure tooling like Kubernetes and Terraform.
• Proven experience designing and operating highly performant, observable backend systems.
• Practical experience or deep familiarity with the modern AI ecosystem (e.g., serving open-source models, vLLM, Ray, model routing, or evaluation frameworks).
• Track record of owning technical projects end-to-end with high autonomy.

Responsibilities

• Build and maintain infrastructure to host and serve open-source LLMs reliably on cloud/GPU systems.
• Implement intelligent model-routing frameworks to optimize performance, cost, and latency.
• Develop evaluation and benchmarking tooling (Evals) to test, validate, and compare model performance across use cases.
• Set the technical direction for operating scalable LLM infrastructure company-wide.
• Build model-routing architecture (e.g., LiteLLM integration) to dynamically direct requests across internal and external models.
• Provision and manage high-performance GPU infrastructure for serving open-source LLMs.
• Build evaluation frameworks (Evals) that enable engineers and data scientists to benchmark model quality against production requirements.
• Drive key cost-optimization and infrastructure efficiency initiatives without sacrificing system accuracy or reliability.

Benefits

• Top-tier health benefits and life insurance
• Long-term group savings with employer match, through Wealthsimple for Business
• 20 vacation days, 4 wellness days, and unlimited sick and mental health days per year
• 90 days away: work outside Canada for up to 90 days per year
• Employee resource groups, including Rainbow (2SLGBTQ), Women of WS, and Black at WS

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed