Senior Software Developer - Cards

Backend Engineer · Senior · Full Time · Remote

Toronto Headquarters · RemoteCAD 151k – 189k1w ago
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Role

What you'll do.

As a Senior Software Developer on Wealthsimple's Cards team, you'll own the full stack of card infrastructure—from issuance and authorization to transaction processing, disputes, and lifecycle management. This greenfield opportunity lets you build mission-critical payments systems at scale for 4+ million Canadians, combining backend engineering expertise with product judgment and AI-driven development workflows.

Responsibilities

  • Own End-to-End Card Infrastructure Systems: Design, implement, and maintain core card systems spanning card issuance, tokenization, authorization flows, BIN management, transaction processing, card lifecycle management, and dispute infrastructure. Make architectural decisions that balance speed, quality, and scale across the entire card stack.
  • Lead Greenfield Backend Development: Build mission-critical backend systems from scratch in a rapidly evolving card program. Take ownership of complex, end-to-end projects from technical design through implementation, launch, and production iteration. Shape architectural patterns and best practices for a growing engineering team.
  • Ensure Reliability and Observability Standards: Build production-grade systems with the reliability and observability standards that payments demand. Implement comprehensive monitoring, error handling, and correctness verification across card transactions and dispute workflows. Handle failures gracefully to maintain user trust.
  • Partner with Product and Design Teams: Collaborate closely with product managers and designers to clarify requirements, surface technical trade-offs, and deliver outcomes rather than just features. Translate complex financial and card network requirements into elegant backend solutions for millions of Canadian users.
  • Optimize Development with AI-First Workflows: Leverage advanced AI tooling and agentic workflows to ship faster and safer. Push the frontier of how the team uses AI while maintaining rigorous engineering judgment. Move beyond AI-as-autocomplete to genuine productivity gains in system design and implementation.
  • Raise Technical Standards Through Leadership: Elevate team engineering quality through design reviews, code reviews, comprehensive documentation, pair programming, and mentorship. Establish patterns and practices that help teammates ship with confidence. Build a collaborative team culture focused on clear communication and shared ownership.

Qualifications

What we look for.

Technical

  • Backend Systems Design and Architecture

    Expertise designing scalable, maintainable backend architectures. Strong understanding of API design, database optimization, transaction handling, and distributed system patterns relevant to payment processing.

  • Production Reliability Engineering

    Deep experience building observable, monitorable systems with comprehensive error handling, logging, and alerting. Understanding of failure modes in financial systems and how to design for high availability and fault tolerance.

  • Card Network Integration

    Experience integrating with card networks and payment processors, understanding authorization flows, settlement processes, and the technical requirements of card issuance and transaction management.

  • AI-Driven Development Workflows

    Practical experience using AI tooling in professional development. Ability to leverage AI assistants for productivity gains while maintaining rigorous code quality and architectural judgment. Know when AI suggestions are wrong and when to override them.

Education

  • Computer Science or Related Field

    Bachelor's degree in Computer Science, Software Engineering, or equivalent professional experience demonstrating strong computer science fundamentals.

Experience

  • 5+ Years Backend Software Engineering

    Demonstrate a proven track record of shipping and maintaining production-grade systems that real users depend on. Show evidence of building scalable, reliable backend infrastructure in professional environments.

  • Payments or Financial Services Background

    Direct experience building and owning backend systems in payments, card, or financial services environments. Ideally with exposure to card issuance, authorization flows, payment rails, transaction processing, or card lifecycle management systems.

  • Greenfield and 0-to-1 Development

    Proven ability to build systems from scratch in ambiguous environments. Experience architecting solutions when requirements aren't fully defined and having the judgment to navigate uncertainty and define a clear path forward.

  • Backend Engineering Fundamentals

    Strong grasp of how money moves through systems, how distributed systems fail, and how to build for correctness and reliability at scale. Understanding of financial transactions, settlement, and the operational requirements of production financial systems.

Skills

Required

  • Backend Web Development

    Strong backend development skills building production systems. Ability to design APIs, manage databases, handle concurrent requests, and optimize performance for millions of users.

  • Systems Design and Architecture

    Ability to architect complex systems at scale. Design for reliability, performance, and correctness. Make trade-offs between speed, quality, and scalability thoughtfully.

  • Financial Systems Knowledge

    Understanding of how financial transactions work, payment settlement, compliance requirements, and the operational complexity of fintech systems. Knowledge of PCI compliance and security standards in payments.

  • Debugging and Problem Solving

    Exceptional ability to debug complex production issues, trace through distributed systems, and root cause problems. Strong analytical thinking and systematic troubleshooting approach.

  • Technical Communication

    Ability to write clear design documents, communicate trade-offs effectively, and guide teams through technical decisions. Strong written and verbal communication to navigate ambiguity.

  • Ownership and Leadership

    Maker-owner mindset with the ability to take responsibility for complex domains and shape them over time. Technical leadership instincts and willingness to mentor and raise team standards.

Preferred

  • Ruby on Rails

    Nice to have

    Experience with Ruby on Rails backend development. Wealthsimple's primary backend language, though depth and learning ability matter more than prior Rails experience.

  • Card Processor Integration

    Nice to have

    Direct experience working with card networks or card processors as an integration partner. Understanding of Visa/Mastercard operations, settlement processes, or BaaS platform limitations.

  • In-House Card Infrastructure

    Nice to have

    Experience building card infrastructure from the ground up rather than layering features on top of BaaS platforms. Understanding of the architectural benefits and challenges of owning the full stack.

  • React or React Native

    Nice to have

    Frontend development experience with React or React Native. Helpful for working across the full stack and understanding frontend constraints in building card products.

  • Fast-Moving Startup Environments

    Nice to have

    Experience in high-velocity engineering environments where individual engineers have broad ownership, influence product decisions, and wear multiple hats.

Tech stack

Languages

RubySQLJavaScript/TypeScript

Frameworks

Ruby on RailsNode.js

Databases

PostgreSQLRedis

Tools

Git and GitHubDatadog or Similar Observability PlatformsDocker and KubernetesCI/CD Platforms

Other

AI Development ToolsMessage Queues and Event SystemsPayment Rails and Settlement Systems

Compensation

Pay and benefits.

Base·CAD 151,200 – 189,000

Equity·Stock options

Benefits

  • Comprehensive Health and Wellness Coverage

    Top-tier health benefits, dental, vision, and life insurance coverage. Unlimited mental health and wellness day support to prioritize employee wellbeing.

  • Long-Term Savings and Retirement

    Group savings program through Wealthsimple for Business with employer matching contributions. Access to Wealthsimple's suite of investment products at employee rates.

  • Generous Time Off

    20 vacation days, 4 wellness days, and unlimited sick and mental health days annually. Work-life balance prioritized through flexible time-off policies.

  • Global Mobility and Remote Work

    Work outside Canada for up to 90 days per year. Hybrid team structure across North America with flexibility to work from different locations. No strict office requirements for eligible roles.

  • Employee Resource Groups and Inclusion

    Participation in ERGs including Rainbow (2SLGBTQ+), Women of Wealthsimple, and Black at Wealthsimple. Commitment to building a diverse, inclusive engineering culture.

  • Professional Development

    Access to learning resources, conference attendance budgets, and mentorship opportunities. Investment in technical growth and career development for senior engineers.

Process

Interview steps.

  1. 01

    Application Review

    Resume and background review to assess experience in backend engineering, payments systems, and relevant technical depth. Initial screening focuses on production experience and card/payments knowledge.

  2. 02

    Technical Screening Call

    Conversation with an engineering team member covering system design fundamentals, past project experience, and approach to building reliable systems. Discussion of AI-driven development workflows and architectural thinking.

  3. 03

    System Design Interview

    In-depth technical interview focused on designing scalable, reliable systems. May cover card authorization systems, payment processing architecture, or similar distributed systems challenges. Emphasis on trade-offs and production considerations.

  4. 04

    Coding and Problem Solving

    Technical assessment of coding skills and problem-solving approach. May include backend system design, API design, or financial/payments-specific algorithmic challenges to assess technical depth.

  5. 05

    Team and Cultural Fit Discussion

    Conversation with multiple team members including the hiring manager and peers on the Cards team. Assessment of collaboration style, ownership mentality, and cultural alignment with Wealthsimple's values around innovation and maker mindset.

  6. 06

    Final Round with Leadership

    Discussion with senior leadership about long-term vision for the card program, your growth as a technical leader, and how you'd approach building world-class engineering standards for the team.

Full posting

Original listing.

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.

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.

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