Senior Software Engineer; Remote

NMI is excited to add a Senior Software Engineer to our growing global team. This role sits within the Protocols team - responsible for building and maintaining mission‑critical services that connect to card payment acquirers and processors. These systems, written primarily in C#, must be scalable, secure, observable, and highly available, ensuring seamless transaction processing for our global customer base.

The Protocols team is part of NMI’s Payments Gateway group, which focuses on developing and maintaining world‑class payment solutions, including PIN pad and card reader integration and processor/acquirer connectivity. As a Senior Engineer, you’ll have a direct impact on how payments flow through the NMI platform, playing a key role in evolving our architecture and building scalable solutions. This role is ideal for engineers who thrive in dynamic environments, lead by example, and are eager to make critical systems more reliable, scalable, and maintainable.

• Contribute to the architecture of highly observable and fault‑tolerant systems.
• Lead technical discussions, participate in code reviews, and drive best practices in maintainability and performance.
• Actively mentor and support the growth of junior team members.
• Collaborate with cross‑functional teams, including Product and QA, to ensure high‑quality delivery.
• Contribute to the evolution of our CI/CD pipelines and observability tooling.
• Participate in the out‑of‑hours on‑call rota to respond to incidents impacting payment flow.

• Bachelor’s degree in Computer Science, Information Technology, or equivalent experience.
• Minimum of 5 years of experience in developing complex software applications in a commercial environment.
• Advanced proficiency in C# (preferred) or Java, with strong understanding of object‑oriented design principles.
• Deep understanding of the full software development lifecycle (SDLC) and agile methodologies.
• Experience with relational databases (e.g., MySQL, SQL Server, Oracle).
• Strong knowledge of security best practices (e.g. OWASP, PCI, SOC2, HIPAA).
• Proficiency with Google Cloud Platform (GCP), Amazon Web Services (AWS), or similar cloud environments.
• Demonstrated experience applying modern software development practices in a collaborative, agile environment.
• Excellent communication skills, with a proven ability to mentor others and contribute to a strong team culture.
• Experience with logging systems (such as Logz.io) and optimizing logs preferred.
• Experience with containerization (e.g. Kubernetes, Docker, etc.) preferred
• Experience with monitoring and alerting systems (e.g. Data Dog, New Relic, etc.) preferred

• Annual bonus scheme dependent on individual and company performance
• Annual salary of £48,000 - £58,000
• 25 days holiday each year (+ bank holidays + 1 day after each year of service with up to a max. of 30 days)
• Workplace pension scheme
• Private medical insurance (upon 30 days of employment)
• 7 hours per day, 35 hours per week
• A remote first culture
• Great work‑life balance with our Flexi‑time policy
• Family Friendly policies (Enhanced Maternity and Paternity Pay and Shared Parental Leave).
• A chance to develop with an allocated company training budget
• Bike2
  
  Work Scheme
• Lifeworks, an Employee Assistance Programme which offers wellbeing, family and financial support services, such as assessments, resources and even 1:1 counselling sessions. It also offers interesting perks such as discounts on gyms, restaurants, high street retailers and cinema tickets
• A strong commitment to employee wellbeing including mental health first aiders
• Employee referral scheme with generous financial reward
• Bonusly colleague reward scheme

We’re looking for creative and passionate people who share our vision of making payments easy. If that sounds like you and you meet the requirements above, then please click on ‘Apply for this job’!

We are an Equal Opportunities employer and will provide reasonable support throughout the recruitment process to applicants who have a disability. Please let us know in advance so that any support, aids or adaptations can be put in place to assist you.

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