Senior Backend Software Engineer Jobs in Toronto, ON

Our software engineers at Epistemix show a clear passion for quality and love to bring software to life. You are energized by the idea of building something new and want to work on problems that matter.

In order to do this job well, you must be a curious and eager problem solver with a hunger for building well-designed, high-quality solutions. You have a passion for great work and strive to produce simple solutions to complex problems. Knowing there are always multiple answers to a problem, you know how to engage in a constructive dialogue to find the best path forward.

The most consequential decisions in public health, life sciences, insurance, and enterprise strategy share a common problem: they involve human behavior, network effects, and downstream effects that cannot be safely tested before action is taken. Traditional analytical techniques built on historical data were not built for this. Epistemix was.

We build simulation and data-driven modeling tools that let leaders visualize how strategies will unfold across populations and systems before they commit resources. By clarifying which variables drive outcomes, where leverage exists, and how they interact, we help organizations move from uncertainty to conviction. Getting these decisions right means faster interventions, better-allocated resources, and measurable improvements in human and economic outcomes. We exist to make that possible.

Our platform gives organizations access to realistic, high-resolution population data and the modeling infrastructure to run scenario planning at scale. Together, these capabilities let decision-makers stress-test strategies in a controlled environment before deploying them in the real world across healthcare, consumer industries, insurance, and government. We are approaching our Series B and actively building the team that will define what comes next.

As a Senior Back-End Software Engineer, you will be at the forefront of our product's evolution. Your key responsibilities will include:

• Design, develop, and maintain clean, testable, and highly maintainable code, ensuring top-tier performance and reliability.

• From initial requirements gathering to deployment and ongoing maintenance, take full ownership of the software development lifecycle, ensuring seamless delivery and operation.

• Design, build, test and deploy a highly scalable and resilient system architecture that supports current needs and future growth.

• Define the technical direction for engineering solutions, actively collaborating with internal teams to ensure technological advancements are perfectly aligned with the company's strategic goals.

• Bachelor's degree in Computer Science, Software Engineering, or related field, or equivalent work experience

• 7+ years of back-end software development experience,with a significant portion in a senior role.

• Expert proficiency in Python, particularly with FastAPI.

• Strong experience with TypeScript for backend development (Node.js/NestJS experience is a plus).

• Deep hands-on experience with AWS cloud services, including but not limited to EC2, EKS, Lambda, S3, RDS, DynamoDB, SQS, SNS, CloudWatch, and IAM.

• Proven experience designing, building, and operating microservices architectures.

• Extensive experience with Kubernetes for container orchestration.

• Expertise in Infrastructure as Code (IaC) using Terraform.

• Hands-on experience with Atlantis for Terraform pull request automation.

• Demonstrated experience or strong understanding of data science orchestration platforms, such as Prefect.io.

• Solid understanding of relational and NoSQL databases, including advanced querying, optimization, and data modeling.

• Experience with API design principles (RESTful, GraphQL) and security best practices (OAuth2, JWT).

• Strong understanding of distributed systems concepts, asynchronous processing, and message queues.

• Experience with CI/CD pipelines and tools (e.g., GitHub Actions, Jenkins).

• Strong communication and interpersonal skills, with the ability to articulate complex technical concepts clearly.

• Ability to work effectively in a fast-paced, agile environment.

By joining Epistemix, you will become part of a collaborative and rapidly growing team that values curiosity and creativity. We are fully remote, with team members in the United States and Europe. Benefits include:

• Equity & Incentives – Participation in our stock option program.

• Flexible Time Off – Autonomy to manage your schedule and work-life balance.

• Health, Welfare and 401(k) Programs – Eligibility for benefits (for U.S. employees).

• Meaningful Impact – Apply your creative talents to revolutionize data-driven decision-making and make a real-world difference.

This is a remote position open to applicants located in the United States. Candidates must possess the legal right to work in their intended work location, as we are currently unable to sponsor or transfer employment visas for any country, including the United States.