Senior Software Engineer, Backend (AI Platform)

About the Position

At Returnly, we exist for the moments that matter-giving people a clear, predictable way to pay over time, with no hidden fees, no surprises, and no tradeoffs on what matters most.

We are seeking a Senior Software Engineer, Backend (AI Platform) to join our AI Platform team. This role is pivotal in building and governing AI systems that scale across millions of users and their transactions. You will be responsible for designing and building gateway, runtime, and evaluation services that ensure reliability, security, and scalability.

Responsibilities

• Plan, execute, and own technical decisions and projects within the AI Platform team, from design through launch and on-call.
• Design and build the gateway, runtime, and evaluation services that take AI workloads at Returnly from pilot to production, securely scaling across millions of users and their transactions.
• Make AI spend attributable and governable: build the identity, quota, routing, caching, and failover controls that let teams adopt new models and tools without re-solving the same platform problems.
• Partner with security, infrastructure, and product engineering teams to set the guardrails for agentic workloads and the on-behalf-of identity model for tool access.
• Create and monitor metrics for your team's systems, and own the operational health of what you ship: monitoring, alerting, runbooks, and on-call.
• Set and improve code review and design standards, and advocate for them beyond your team through writing and tech talks.
• Use AI tools and agentic workflows every day as a multiplier for your own code, design review, and operations, and push the team on what a small AI-native team can deliver.
• Educate, mentor, and grow engineers in the team, and drive best practices around design, coding, and testing.

Requirements

• 4+ years of experience designing, developing, and launching backend systems at scale using languages like Python or Kotlin.
• Experience developing highly available distributed systems using technologies like AWS, MySQL, and Kubernetes.
• Practical experience building with LLMs, agents, or AI frameworks in production: inference APIs, LLM gateways (LiteLLM or similar), MCP, tool calling, evals, or agent runtimes.
• Understanding of AI usage and the infrastructure needed to support and leverage AI workloads across different disciplines.
• Experience defining a technical plan for the delivery of a significant feature or system component with an elegant, simple, and extensible design. You write high-quality code that is easily understood and used by others.
• Proficiency at making significant changes in a large code base, and have developed a suite of tools and practices that enable you and your team to do so safely.
• Strong verbal and written communication skills that support effective collaboration with our global engineering team.
• Either equivalent practical experience or a Bachelor’s degree in a related field.

We Offer

• Competitive salary: CAD 153,000 - 213,000 per year + Equity
• Health coverage at no cost: We cover 100% of premiums for employees and their dependents.
• Spending stipends: Monthly stipends support your tech setup, and the ability to choose health and wellness options that are right for you.
• Time off to recharge: Flexible time off and generous holiday calendars help you rest when you need to.
• Own a piece of what you build: Our employee stock purchase plan (ESPP) lets you buy Returnly stock at a discount.

About the Company

Returnly is a remote-first company with flexibility built in. Most roles can be done from almost anywhere within the country of employment. Some positions may occasionally require in-person work at a Returnly office, and a few are office-based due to the nature of the work. All new hires will be invited to attend an in-person onboarding experience.

We’re committed to providing an inclusive interview process, including accommodations for candidates with disabilities. If you need support, we’re happy to help.

For positions based in specific Canadian provinces: Returnly considers qualified applicants with arrest and conviction records, as required by law.

By clicking "Submit Application," you acknowledge that you have read Returnly's Global Candidate Privacy Notice and consent to the use of your personal information as described.

Apply now to join our team and help us build the future of AI at Returnly.