Senior Software Developer - Cards

Build something people love Wealthsimple is Canada’s leading financial innovator. The company offers a full suite of simple, sophisticated financial products across managed investing, do-it-yourself trading, cryptocurrency, tax filing, spending and saving. Wealthsimple currently serves more than 4 million Canadians and holds over $155 billion in assets under administration. The company was founded in 2014 by a team of financial experts and technology entrepreneurs, and is headquartered in Toronto, Canada. We're proud of what we've built — and we're just getting started. Read our Culture Manual and learn more about how we work . About the role As a Senior Software Developer on the Cards team, you'll own meaningful slices of the card stack end to end — from card issuance and authorization through transaction processing, disputes, rewards, and card lifecycle management. This is not a features-on-top-of-a-BaaS role. We're building card infrastructure in-house, and the person we hire will be able to say they built it. You'll bring strong technical judgment, a bias toward action, and a deep sense of ownership. You'll work closely with product managers, designers, and engineers to turn complex, high-stakes problems into simple, reliable experiences for millions of Canadians. What you'll do Shape and own greenfield work in a space that's still early for Wealthsimple — our card program is still in its early years and there's significant greenfield building ahead; if you've built something from scratch before, that experience will go far here Own complex, end-to-end projects across the card stack — from technical design through implementation, launch, and iteration Build and improve the backend systems that power our card products, with a focus on reliability, performance, and correctness Work on core card infrastructure: card issuance, tokenization, authorization flows, BIN management, transaction processing, card lifecycle management, and dispute infrastructure Make thoughtful architectural decisions and help the team balance speed, quality, and scale — influence what we build, how we build it, and where we go next Partner closely with Product and Design to clarify goals, surface trade-offs, and deliver outcomes — not just features Build with the reliability and observability standards that card journeys demand — a declined tap or a poorly handled dispute is felt immediately by our members Leverage AI-centric workflows to ship faster and safer — we invest heavily in AI tooling and expect senior engineers to push the frontier of how we use these tools Raise the technical bar through design reviews, code reviews, documentation, pairing, and mentorship Help create a team culture where people communicate clearly, learn quickly, and take ownership together What you bring 5+ years of professional software engineering experience and a track record of shipping production-grade systems that real users depend on Experience building and owning backend systems in a payments, card, or financial services environment — ideally with direct exposure to card issuance, authorization, payment rails, or card lifecycle management Strong backend engineering fundamentals — you understand how money moves, how systems fail, and how to build for correctness at scale A maker-owner mindset: you're looking for a place to plant a flag, take ownership of a growing domain, and shape it over time — motivated by building the best card program in Canada, not just shipping the next ticket Comfort with ambiguity and greenfield work — you've built something from 0→1 before and thrive in an environment where not everything is defined yet An AI-first development workflow that doesn't compromise on rigour — you've moved beyond AI as autocomplete into genuinely agentic workflows, and bring the engineering judgment to know when the model is wrong Product judgment: you care about the member problem, can simplify complexity, and know when to iterate versus when to invest for the long term The ability to navigate ambiguity, define a path forward, and bring others along through clear written and verbal communication Technical leadership and mentorship instincts — you raise the bar through your code, your reviews, your design documents, and the way you support your teammates A collaborative, low-ego approach to engineering and a willingness to give and receive candid feedback Nice to have experience Experience working directly with card networks or card processors — on either side of the integration Experience building card infrastructure in-house rather than on top of a BaaS platform Ruby on Rails or experience in a comparable backend language — Ruby is helpful but not a requirement; depth and willingness to ramp matter more React and/or React Native experience Experience in a fast-moving environment where engineers have broad ownership and meaningful influence over product decisions Why Wealthsimple? 🌸 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 🌎 We are a hybrid team with over 1,500 employees across North America. The people are one of the best parts of working here: you'll collaborate with incredibly talented, curious, and driven teammates who are deeply committed to doing great work. *Unlimited paid sick days, Wellness Days and the 90 day away program do not apply to certain roles. ICYMI Technology & Innovation at Wealthsimple: We move quickly and build thoughtfully. That means we're always looking for better ways to work — whether that's new tools, AI, or rethinking how we approach a problem. We don't expect you to have all the answers, but we do expect curiosity and a willingness to evolve alongside the products we're building. Inclusion Statement: We're building products for a diverse world, and we need a diverse team to do it well. We strongly encourage applications from everyone, regardless of race, religion, colour, national origin, gender, sexual orientation, age, marital status, or disability status. Accessibility Statement: We're committed to an accessible hiring experience. If you need any accommodations throughout the interview process, please let us know — we'll work with you to make sure you have what you need. We also welcome any feedback on how we can better accommodate candidates with accessibility needs. AI in Hiring: We may use artificial intelligence (AI) tools to support parts of our hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our team but don't replace human judgment – all final hiring decisions are made by people. If you have questions about how your data is used, reach out to us.