Senior Software Engineer

NMI is looking for a passionate Senior Software Engineer to join our Development team as a result of NMI's continued growth and investment in the underlying systems. This role reports to the Engineering Manager. As a senior developer with strong experience in C# and/or PHP, you will join a team of industry-leading experts that are talented, ambitious and want to drive the continued development of our payment processing services. Our developers are responsible for software services and deliverables that support the processing of billions of transactions for hundreds of thousands of merchants every year. These applications have to be efficient, reliable, redundant, secure, highly-available and scalable. A background in the development of accounting or billing systems is preferred for this specific role. AI-assisted development is core to how we build at NMI. Our engineers work with Claude and Cursor every day, and we expect you to use them fluently: to move faster, to raise quality, and to spend more of your time on the problems that need human judgement. About NMI NMI, a global leader in payment technologies, allows software and sales professionals to deliver payment innovations to their clients without having to build payment expertise in house. NMI enables our partners with choice, and challenges the one-size-fits-all approach to payments. You've probably used NMI in the last 24 hours without even realizing it. We're the platform that powers success for innovative tech created by SMBs, entrepreneurs and fintech startups. We're creative problem solvers who help visionaries smash through boundaries and think beyond what's possible so they can think about what's next. But we're not just built for the tech savvy. We democratize the latest payments technology so that everyone can realize the benefits of easy payments across the full spectrum of commerce. Our mission is to use our expertise to enable more payments, in more ways and more places. We provide ISOs, Fintech Innovators and Technologists the freedom to focus on what they do best, liberating them from restricted payment solutions and giving them access to the latest payment technology now and in the future. How We Work - Our Core Values - Be a Good Person, It's Simple. We treat everyone fairly and with respect.

We lead with kindness, humility and integrity. We take the time to understand each other and our customers. And we serve with care, because customers are never a transaction, and always our focus - Align, Trust & Go. We debate openly, listen carefully and challenge thoughtfully. Once we decide, we move forward together - holding ourselves accountable to our commitments, and focusing on what matters most to our customers. That alignment creates momentum. - Raise the Bar. Good enough isn't enough. We stay curious, measure everything, stay honest about progress and keep pushing ourselves to think creatively. We drive change, again and again. And leave things better than we found them. When we raise the bar, our customers feel it too. Key Responsibilities: - Design, develop, and maintain core billing and invoicing systems using C# and PHP technologies. - Use AI-assisted development tools, specifically Claude and Cursor, as a core part of your daily engineering workflow across design, implementation, testing, refactoring, and comprehension of large existing codebases. - Remain fully accountable for everything you ship: review AI-generated code with the same rigor you apply to any other contribution, verifying correctness, security, performance, and maintainability before it reaches production. - Take ownership of architectural and design decisions for billing system components. - Lead technical discussions, participate in code reviews, and drive best practices in maintainability and performance. - Mentor and support the growth of junior team members, including coaching on effective and safe use of AI development tools.