Senior Software Engineer - Cards

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.

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 experience: issuance, physical card shipping, spend controls, lifecycle management, authorization, money movement, settlement, reporting, and the underlying infrastructure. We're a full-stack team focused on making 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.

Responsibilities

• Lead projects from idea to tech spec to implementation to launch, collaborating with product managers, engineering managers, tech leads, and teammates.
• Master the mechanics of debit and credit cards under the hood (authorization, clearing, settlement, disputes) and apply that knowledge daily.
• Build full-stack features, ranging from customer-facing card experiences to backend money-movement infrastructure.
• Maintain operational excellence and high observability for business-critical financial systems.
• Mentor other engineers and raise engineering quality through design reviews, code reviews, and pair programming.
• Cross-collaborate with product, design, operations, risk, compliance, and sales teams.

Qualifications

• Strong full-stack development experience, a product mindset, and strong systems thinking.
• Proven background making complex architectural decisions and articulating technical trade-offs.
• Experience building and maintaining production systems where correctness and financial reliability are critical.
• Clear communication skills with the ability to handle ambiguity and mentor peers.
• Proficiency with or willingness to learn our primary tech stack: Haskell and TypeScript.
• Bonus: Prior experience in fintech, payments, or card issuing.

Total Rewards & Compensation

Mercury offers a competitive total rewards package including base salary, equity (stock options/RSUs), and comprehensive benefits.

Target base salary ranges:

• US Employees: $166,600 — $208,300 USD
• Canadian Employees: $157,400 — $196,800 USD