Senior Software Engineer - Cards

Mercury; Canada; On-site; CAD 157,000 - 197,000; Full time

Job summary

Mercury is seeking a Senior Software Engineer in Canada to own and advance the Mercury card stack—from issuance and spend controls to settlement and reporting. You will design scalable systems, collaborate with product and operations, and deliver features that move money reliably and securely.

You will work with a strong focus on reliability, ownership, and customer experience, mentoring teammates and improving observability across services.

Qualifications

• Experience delivering scalable full-stack systems.
• Ability to lead projects end-to-end and influence cross-functional teams.
• Familiarity with fintech limits, risk, and reliability requirements.
• Strong mentoring and code-review capabilities.

Responsibilities

• Lead projects from idea to tech spec to implementation to launch with PM/EM/tech lead and teammates.
• Understand debit/credit processing and apply that knowledge daily.
• Build features across the stack, from user experiences to backend money movement.
• Improve observability and reliability of Mercury’s systems.
• Mentor engineers and raise engineering quality through reviews and collaboration.
• Collaborate with product, design, operations, risk, compliance, sales, and other teams.

Skills

Full-stack development

Architectural decision-making

Mentoring

Systems thinking

Strong communication

Haskell

TypeScript

Job description

As the story goes, in 1949 Frank McNamara finished dinner at a New York restaurant and found he'd left his wallet in another suit. His fix was a card that let members eat now and pay later. That card became Diners Club, widely credited as the first multipurpose charge card. It was a piece of cardboard and a promise: the restaurant trusted the card, the card trusted the member, and someone had to make sure the money actually moved.

More than seventy-five years later, the promise hasn't changed, but the machinery has. When a Mercury customer taps their card, the request goes from the merchant's terminal through an acquirer and a card network to us. In a fraction of a second, we check the balance, apply the customer's spend controls, screen for fraud and say yes or no. After that comes clearing, settlement, disputes and reporting, and every cent has to reconcile.

Cards are the way Mercury customers spend money. The Cards Integration team owns the whole Mercury card, not just the swipe: issuance, physical card shipping, spend controls, lifecycle management, authorization, money movement, settlement and reporting, and the infrastructure underneath. We're a full-stack team, and our job is to make the Mercury Debit and IO cards reliable, correct, useful, and innovative.

We're looking for a Senior Software Engineer who thinks deeply about systems architecture, cares about the customer experience, and will dive into any problem to move the team forward. We value high ownership, working in pairs and teams rather than alone, and attention to detail. Those matter when you run systems held to four nines of reliability, and everyone around you will care about them too.

In this role, you will

• Lead projects from idea to tech spec to implementation to launch, working with your PM, EM, tech lead, and teammates at each stage. When you lead a project, it's yours to see through.
• Learn how debit and credit cards actually work under the hood (authorization, clearing, settlement, disputes) and use that knowledge every day.
• Build features across the stack, from the card experiences customers use to the backend systems that move money.
• Help keep our operations excellent. Our systems are some of the most observable at Mercury, and with great observability comes great responsibility.
• Mentor other engineers and raise engineering quality through design reviews, code reviews, and collaboration.
• Work with product, design, operations, risk, compliance, sales, and many other teams.

You should

• Have strong full-stack experience, a product mindset, systems thinking, and a knack for getting things across the line.
• Have made architectural decisions on complex systems, and be able to explain your reasoning and the trade-offs.
• Be excited to put new features in customers' hands, and care just as much about keeping existing ones working like a charm.
• Care about correctness in systems where failure has real financial consequences.
• Communicate clearly, handle ambiguity well, and enjoy mentoring others.
• Be comfortable with our tech stack (Haskell and TypeScript) or be ready to learn.
• Bonus: experience in fintech, payments, or card issuing.

We encourage you to try our demo site if you're interested in applying for the role.

*Mercury is a fintech company, not an FDIC-insured bank. Banking services provided through Choice Financial Group and Column N.A., Members FDIC.*

Mercury values diversity & belonging and is proud to be an Equal Employment Opportunity employer. All individuals seeking employment at Mercury are considered without regard to race, color, religion, national origin, age, sex, marital status, ancestry, physical or mental disability, veteran status, gender identity, sexual orientation, or any other legally protected characteristic. We are committed to providing reasonable accommodations throughout the recruitment process for applicants with disabilities or special needs. If you need assistance, or an accommodation, please let your recruiter know once you are contacted about a role.

Total Rewards

The total rewards package at Mercury includes base salary, equity (stock options/RSU), and benefits.

Our salary and equity ranges are highly competitive within the SaaS and fintech industry and are updated regularly using the most reliable compensation survey data for our industry. New hire offers are made based on a candidate’s experience, expertise, geographic location, and internal pay equity relative to peers.

Our target new hire base salary ranges for this role are the following:

US employees (any location): $166,600 — $208,300 USD

Canadian employees (any location): $157,400 — $196,800 CAD