Senior Software Developer, Build Platform

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 Build Platform Team At Wealthsimple, the Build Platform team is on a mission to make developing great software fast, intuitive, and enjoyable. We believe engineers should focus on building incredible features for our clients, not fighting their environment. Our job is to clear the path. We do this by treating our platform as a product. Our internal developers are our customers, and their success is our primary measure of impact. As a Developer on our team, you won't just be building tools; you'll be shaping the entire developer journey at Wealthsimple. From their first day onboarding to their thousandth code submission, you'll be making the experience seamless. You will support a diverse engineering organization that uses Ruby, Python, Kotlin, and TypeScript to build the future of finance. Your work will directly empower hundreds of developers to ship high-quality, secure code to millions of users with confidence and speed. The most interesting problem on our plate right now is AI. When agents write a large share of the code, the bottleneck stops being how fast you can produce a change and starts being how fast you can trust one. That makes verification the constraint on the whole company: reproducible environments, test signal you can believe, and feedback loops tight enough that an agent catches its own mistakes before a human ever sees them. Building that layer is the team's biggest bet, and this role sits at the centre of it. In this role you’ll have the opportunity to: Build the substrate for agentic development. You'll roll out containerized development environments across hundreds of services so that engineers and coding agents alike get reproducible, isolated, fast environments to work in. This eliminates "works on my machine" and it is the foundation everything AI-native depends on. Build the verification layer for AI-native development. As agents generate more of our code, proving a change is safe becomes the constraint on how fast the whole company ships. You'll build the systems that give agents and developers a trustworthy answer in seconds rather than hours. Make test signal fast, deterministic, and actionable. Flakiness a human can shrug off is fatal to an agent iterating unattended. You'll attack flake detection, test selection, and failure output that is legible enough to act on without a person interpreting it. Modernize the core libraries and CLI that underpin our microservices architecture, automating developer machine setup and replacing legacy tools with safer, auditable alternatives. Well-shaped tooling is what makes humans and agents both effective. Solve the hard testing problems underneath all of it. You'll build robust backend mocking solutions, and enable isolated testing of asynchronous, event-driven workflows in ephemeral environments. Define and measure operational excellence at scale. You'll help build automated scorecards that give every team clear, actionable insight into the health of their services, covering everything from dependency management to monitoring and scalability. What you’ll bring: 7+ years of experience in software development as part of a team, preferably a platform-oriented team. 7+ years experience with any of the following: Ruby, Python, Typescript, Kotlin. Experience designing, building, and maintaining internal libraries, frameworks, or tooling used by other engineering teams. Hands-on experience with AI-assisted development. You've used coding agents on real production work, you know where they break down, and you have opinions about what makes them effective. A builder's instinct for AI tooling. You've built with LLMs rather than only used them, and you've thought hard about how to evaluate whether what they produce is actually correct. Curiosity and a deep interest in a fast, reliable, streamlined developer experience. You're driven to understand your users, eliminate complexity, and build elegant solutions to their pain points, and you keep a close eye on where the industry is heading. A collaborative spirit and a passion for mentorship. You believe in making your colleagues successful and enjoy coaching other developers. A data-informed approach to decision-making. You are comfortable using metrics to identify opportunities and measure the impact of your work. 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.