Senior Software Development Engineer; Platform & API Architecture

Job Title - SR Software Development Engineer in Platform & API Architecture

Client

Location:

Brookfield, WI

Work Environment:
Remote, with some travel to headquarters

Salary: $150,000 to $180,000 plus bonus, plus benefits, and a lot more

Term:
Direct Hire

Please, no 3rd party companies are allowed to work on this position.

You will help us build the platform that transforms how businesses and governments move money.

We’re redefining how organizations manage deposits  combining fintech innovation, treasury intelligence, and secure infrastructure into a unified platform, we help public- and private-sector clients turn cash into a strategic asset—automating complex workflows with speed, accuracy, and real-time visibility.

We’re launching the first version of our platform soon and stepping into a massive, underserved market. This is the rare moment where you can join early and help shape the architectural foundation of a high-growth fintech product—without the chaos of a true startup and with the impact of building an industry-changing platform.

If you’re a builder at heart, someone who thrives in ambiguity and wants to create something entirely new, you’ll be a perfect fit.

• You’ll architect the future of our platform—not inherit legacy.
• You’ll write code every day while guiding high‑level design decisions.
• You’ll partner directly with the CTO and influence every primary technical choice.
• You’ll help define new revenue models: APIs, integrations, platform licensing, white‑label solutions.
• You’ll build for scale in a regulated industry where reliability and security are everything.

This is the ideal role for an engineer ready to grow into an architect or platform owner.

• Progress the platform from an internal system to a scalable, fully productized solution.
• Architect for multi‑tenancy, modular deployment, and white‑label flexibility.
• Build with future scale in mind—extensibility, observability, performance, and onboarding velocity.
• Participate in architectural reviews and help define engineering standards.

• Lead the design of robust REST APIs that connect to banking systems, retail POS infrastructure, cash logistics providers, public‑sector financial systems.
• Own API versioning, governance, and lifecycle management as we scale to partner‑facing services.
• Build reusable, secure integration patterns for future enterprise customers.

• Extend our configurable rules engine to support complex financial workflows: reconciliation, fee structures, compliance logic and exception handling, SLA calculations.
• Build systems that enable non‑engineers to configure business logic through UI‑ or DSL‑based tools.

• Design systems built for availability and multi‑client isolation.
• Implement secure access controls, encryption, logging, and audit trails.
• Architect for compliance with SOC2, PCI‑DSS, and public‑sector requirements.

• Provide architectural guidance across the engineering team.
• Translate customer needs and business problems into scalable technical designs.
• Influence technical standards, code quality, and platform velocity.
• Act as a strategic partner to leadership, exploring new delivery models.

• 6+ years in back‑end engineering, with experience touching architecture or platform leadership.
• Strong hands‑on expertise with C# and .NET.
• Proven success in building multi‑tenant platforms, complex APIs, or B2B enterprise systems.
• Deep understanding of: API design & versioning, modular/microservice architecture, event‑driven systems, secure system design (OAuth2, JWT, RBAC, encryption), configurable business logic and rules engines.
• Experience working in regulated or compliance‑driven environments is a strong plus.

Every feature you build will directly shape how money moves through corporations, retailers, municipalities, and financial institutions. You’ll help create the system that supports new business models, new customers, and the future of our platform.

This is more than a senior engineering role—it’s a chance to help architect a category‑defining fintech product from the ground up.