Senior Software Developer (Book of Record, Leverage)

Join Wealthsimple, a fast-growing fintech company, as a Senior Software Developer. In this role, you will take ownership of backend systems that track balances and calculate buying power and collateral. You will work closely with Product, Design, and other engineering teams to turn complex financial logic into simple experiences for users. You will also help evolve the architecture as the company grows and mentor other engineers.

• Conception, construction and operation of backend services that manage balances, margin, buying power, collateral, and lending.
• Ownership of significant scope from technical design to production, including solving complex problems related to real-time correctness and high availability.
• Mentoring and developing engineers through pairing, code review, and feedback, while also raising the bar on quality and operational excellence.
• Strong backend engineering skills and sound judgment about system design, reliability, and trade-offs
• Strong software quality habits: you write well-tested, maintainable and observable code. You make the codebase and the people around you better through your reviews
• Several years (5+) of professional software engineering experience, with a track record of building and operating critical production systems that people or businesses depend on
• Clear, steady communication. You work well with Product, Design, and other engineering teams, share context early, and ask questions before you're stuck rather than disappearing down a hole
• Experience building services that are low-latency and highly available
• You take production ownership seriously and stay calm and methodical when things go wrong
• Enthusiasm for AI-assisted development, and interest in helping shape what excellent, rigorous AI-assisted engineering looks like on our team
• Curiosity about the "why" behind the systems - not just the code, but the financial reality it represents and the clients on the other side of it
• We work primarily in Kotlin, with Kafka and GraphQL in the mix - deep experience in a comparable stack matters more than an exact match, and we'll help you ramp on ours
• Experience in fintech, banking, trading, or another regulated, high-stakes domain - ideally at a fast-moving, high-growth company
• Familiarity with ledgers, reconciliation, or financial-correctness problems
• Experience with event-driven architecture and stream processing (Kafka, Flink, or similar)
• Familiarity with Apollo Federation or Kubernetes
• Exposure to margin, options, futures, or lending products
• You're comfortable with ambiguity and do your best work in a domain where the problems are consequential and rarely perfectly clean
• You're collaborative and generous by default: you share what you know, invest in the people around you, and help the whole team get better
• You're detail-oriented without losing the bigger picture - you care deeply about correctness, and about the experience for the client on the other side of it
• You take ownership end-to-end - from the design to the code to making sure it holds up in production
• If this sounds like the kind of work you want to do, we'd love to hear from you - even if you don't tick every single box above. Depth, judgment, and a genuine interest in the problem count for a lot
• You're curious and always learning - open to new ideas, new perspectives, and new ways of working