Senior Backend Engineer in Toronto

We’re a software company at the start of building a brand-new, highly visible SaaS application. This is a rare opportunity to help shape the technical foundation: you’ll help set technical direction, establish engineering standards, and ship foundational capabilities that will shape the product for years. We’re looking for a motivated senior engineer who thinks and builds with an AI-first mindset—someone excited about agentic AI workflows, automation, and using modern AI tooling to accelerate delivery without compromising quality. This project will be using AI-Development Life Cycle (AI-DLC) to drive the creation, testing and deployment of this application. This is a tremendous opportunity to be fully supported in an AI first approach.

In this role, you’ll design and implement core backend systems using .NET/C# and proven architectural patterns such as Event Sourcing, CQRS, Domain-Driven Design (DDD), and Vertical Slice (vertical event-sourced) architectures. You’ll work in a cloud-native environment leveraging AWS, PostgreSQL, RabbitMQ, and Docker, contributing to a platform built for scale, reliability, and rapid iteration. You’ll also be a technical leader—taking ownership, mentoring others, and helping define best practices for a high-performing team.

Responsibilities

• Own major components of a new SaaS platform from design through production
• Build event-sourced, CQRS-based services in C#/.NET using DDD principles
• Design clean domain models, message contracts, and integration patterns using RabbitMQ
• Deliver cloud-ready solutions using Docker and AWS (deployment, observability, reliability)
• Apply an AI-first approach to engineering: agentic AI tools, automated workflows, code generation/review, test generation, and productivity accelerators
• Partner with product and engineering leaders to define architecture, standards, and delivery practices
• Write high-quality, well-tested, maintainable code and raise the bar through reviews and mentorship

Must Have

• AI-first mentality with practical experience using AI tools to accelerate development
• Senior-level experience building production systems with C#/.NET
• Hands-on experience with Event Sourcing and CQRS in real-world systems
• Strong working knowledge of Domain-Driven Design (DDD)
• Experience with Vertical Slice architecture (or similar modular service boundaries)
• Solid experience with PostgreSQL
• Experience with asynchronous messaging and integration patterns, ideally RabbitMQ
• Experience containerizing services with Docker
• Experience building/operating cloud-hosted applications, ideally on AWS
• Familiarity with agentic AI concepts (autonomous workflows, tool-using agents, orchestration, evaluation/guardrails) and excitement to apply them in day-to-day engineering
• Strong ownership mindset: you ship, you improve, you operate, you lead

Nice to Have

• Experience with MartenDB
• Experience with Wolverine
• Experience designing multi-tenant SaaS systems (auth, billing, isolation, scaling, observability)
• Familiarity with modern DevOps/IaC practices (e.g., Terraform/CDK), CI/CD, and distributed tracing