Senior Software Engineer - Virality

Since the dawn of aviation, pilots have faced the constant challenge of air resistance, much like sailors navigating the friction of water. Amidst this relentless struggle, the trim tab emerges as an ingenious yet understated marvel. Just as the wheel revolutionized transportation by easing movement over land, the trim tab simplifies flight, allowing for smoother navigation through the skies. It embodies the elegance of simplicity in engineering, transforming the demanding task of controlling an aircraft into a more graceful and manageable endeavor.

At Mercury, we are committed to crafting an exceptional banking\* experience for startups. Our team is passionately focused on ensuring our product not only meets but anticipates the needs of our customers.

Our product engineering group is growing and we’re looking to hire a senior full-stack engineer. We’re a team of pragmatic, product-minded engineers motivated by the desire to create lovable products that rescue our customers from frustrating, expensive legacy industry tools.

About the Virality Team

The Virality team exists to grow Mercury through our existing customers via network effects. We build experiences that make using Mercury contagious: when one business uses Mercury, their customers, partners, vendors, and clients want to join too.

What You’ll Work On

As a Senior Software Engineer on the Virality team, you’ll help Mercury grow organically by building delightful, interconnected product experiences. Some examples of projects and problem spaces include:

• Building products for high-value, well-connected nodesCreating tools for accounting firms, VCs, and incorporators that help them manage and onboard multiple client accounts, e.g. multi-entity dashboards, partner and advisor portals, and lightweight onboarding flows for new standalone products.

• Creating viral payment experiencesMake Mercury-to-Mercury payments instant, secure, and identity-aware so that sending money feels seamless and personal. You’ll help design and build systems that make getting paid by an existing Mercury customer a natural front door to Mercury.

• Building referral and partnership growth loopsDevelop systems that make it effortless for customers and established partners to invite others. Referral links drive a substantial number of Mercury’s monthly signups, and Virality accelerates this behavior to drive compounding, network-driven adoption.

How You’ll Build

You’ll work across Mercury’s product and platform layers to:

• Design scalable systems and data models for interconnected account relationships.
• Build event-driven systems that tie payments, referrals, and onboarding into a cohesive ecosystem.
• Partner with design, product, and data science to prototype and A/B test new virality mechanisms.
• Make architectural decisions that balance experimentation speed with long-term scalability.
• Mentor other engineers and help define best practices for growth-oriented development.

You’ll thrive if you:

• Enjoy exploring ambiguous, 0->1 product spaces with measurable impact.
• Think in terms of loops, ecosystems, and compounding effects, not just features.
• Balance creativity with rigor: you’re excited to experiment, measure, and iterate quickly.
• Care about user experience and how subtle product details drive real growth.

The Ideal Candidate for this Role:

• Has 3-7+ years of demonstrated full-stack experience working at the senior level or higher with a strong sense of ownership, and has demonstrated experience independently driving projects from inception to completion.
• Has full-stack experience, including proficiency in SQL and Haskell, and experience in or an interest in learning Typescript and React.
• Communicates and collaborates effectively with peers and cross-functional counterparts.