Senior Software Engineer

NMI

3h•$115,000 - $130,000•Remote

About The Position

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.

Requirements

Bachelor's degree in Computer Science or equivalent experience.
Minimum of 5 years of experience developing complex software applications in a collaborative, agile environment.
Advanced proficiency in C# and/or PHP, with a strong understanding of object-oriented design principles and design patterns.
Advanced experience with database design, optimization, and performance tuning.
Strong knowledge of security and compliance best practices (e.g. OWASP, PCI).
Excellent communication skills, with a proven ability to mentor others, contribute to a strong team culture, and work with others across teams to move projects forward.
Experience designing and architecting scalable, distributed systems with consideration for performance, reliability, and maintainability.
Ability to translate complex business requirements into technical solutions.
Proven track record of code reviews and maintaining code quality standards.
Proven ability to understand, debug, and enhance complex existing systems with limited documentation and evolving requirements.
Hands-on experience building production software with Claude and Cursor, our standard toolset, and a willingness to make them a daily part of how you work.
Sound judgment about where AI tooling adds leverage and where it does not, including an understanding of how these tools fail in large, legacy or sparsely documented systems.

Nice To Haves

Experience with logging systems (such as Logz.io) and optimizing logs.
Experience with containerization (e.g. Kubernetes, Docker, etc.).
Experience with monitoring and alerting systems (e.g. DataDog, NewRelic, etc.).
Experience with CI/CD pipelines, automated testing, and deployment processes.
A background in the development of accounting or billing systems is preferred for this specific role.

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.
Lead improvements to CI/CD pipelines and development processes.
Implement monitoring, logging, and alerting systems to proactively identify and resolve issues.
Optimize database queries and system architecture to handle growing merchant and transaction volumes.
Implement robust security measures to protect sensitive payment and merchant data and ensure compliance with PCI DSS standards, including when working with AI development tools.
Communicate project status, risks, and technical decisions effectively to both technical and non-technical stakeholders.
Collaborate closely with Product Owners, Developers, and QA teams to ensure successful product releases.
Identify, assess, and mitigate risks, including security risks, throughout the software development lifecycle.
Provide feedback and resolutions to escalated support issues.
Research and evaluate new technologies and methodologies to improve system performance and developer productivity.