Senior Software Engineer - Banking Integration Platform

When the Space Shuttle approached the International Space Station, two vehicles built by different teams, in different countries, with fundamentally different engineering philosophies and systems, had to connect perfectly. The Rendezvous, Proximity Operations, and Docking (RPOD) subsystems were engineered to handle complex mismatches such as different power systems, communication protocols, and technical architectures. Get it wrong, and you have an expensive and potentially catastrophic problem in low Earth orbit.

Mercury announced on December 19, 2025 that we submitted an application to the OCC for a national bank charter and applied for FDIC deposit insurance. In other words, Mercury is building a bank. As part of this work, we will be connecting our modern, product-focused engineering systems to enterprise core banking systems and payment networks built in a different era, with different assumptions and different interfaces. Mercury’s Banking Integration Platform as a Service team is like NASA’s RPOD team, building our integration subsystems that are technically correct and operationally trustworthy.

This is some of the most consequential infrastructure work at Mercury. Every account opening, every monetary transaction, and every balance call will flow through the systems you build. Product teams across the company will depend on clean abstractions that hide the complexity underneath. You'll be one of the few engineers at Mercury who truly understands the full depth of our Bank Core* and all its internal and external integrations.

In this role, you will:

• Build Mercury’s integration with an FFIEC-approved bank core and the connections to payment networks.
• Design internal APIs that give product teams simple, consistent interfaces to complex external systems.
• Handle the messy realities of enterprise integrations such as retries, failures, format mismatches, and downtime.
• Build data pipelines that keep Mercury's systems in sync with our bank core.
• Own monitoring, alerting, and recovery for our most critical external connections.
• Partner with many other teams at Mercury to define clean boundaries and reliable contracts.
• Help shape the technical architecture of Mercury Bank*.

You should:

• Have direct experience with either a bank core that has achieved FFIEC-compliance (such as FIS) or that of a US-based Global Systemically Important Bank (G-SIB) .
• Understand how core banking systems work: accounts, transactions, ledgers, and the data models underneath.
• Be a product-minded engineer who thinks about the developers consuming your APIs, not just the systems you’re connecting to.
• Thrive in environments where you're building something new rather than maintaining something established.
• Be comfortable with our tech stack (Haskell and TypeScript) or ready to learn.
• Have strong opinions about building reliable, maintainable systems.

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

The total rewards package at Mercury includes base salary, equity, 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 - $250,900
• Canadian employees (any location): CAD 157,400 - 237,100

* Unless we are granted regulatory approval otherwise, we are still not a bank, so our standard disclaimer still applies: 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.

#LI-ES1