Senior Software Engineer (C#) in London

NMI is a leading provider of payment gateway solutions, specializing in card-present solutions and payment processing. Our innovative technologies empower businesses to securely accept payments and optimize transaction processes. With a focus on reliability, security, and innovation, we continuously push the boundaries of what’s possible in the payments industry.

We are seeking an experienced Software Engineer to join our Payments Processing group. This group focuses on developing and maintaining world-class payment solutions, including PIN pad and card reader integration and processor/acquirer connectivity.

The Ideal Candidate

The ideal candidate will have extensive experience in C# and a strong grasp of object-oriented programming principles. Candidates with expertise in other object-oriented languages (e.g., Java) will also be considered if they have demonstrable experience with a .NET language.

As a Senior Engineer, you will play a leadership role in designing, developing, and maintaining solutions that integrate PIN pads and card readers into Payment Device SDKs for card-based transactions, including contactless, full Chip-and-PIN, magnetic stripe, and manually keyed transactions. You will be expected to take ownership of technical decisions, proactively address challenges, and contribute to the continuous improvement of our CI/CD pipeline.

Your responsibilities will extend beyond implementation, as you will mentor junior engineers, drive technical discussions, and ensure that our solutions meet high standards of security, performance, availability, and reliability.

Key Responsibilities

• Design, develop, and implement scalable, high-quality software solutions that are secure, reliable, and performant.
• Lead architectural and design discussions, ensuring adherence to best practices and maintainability.
• Write and review high-quality, well-documented code with an emphasis on efficiency and scalability.
• Conduct thorough code reviews, identifying potential errors, inefficiencies, and opportunities for improvement in the codebase.
• Provide technical leadership and mentorship to junior and mid-level engineers, fostering a culture of learning and collaboration.
• 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.
• Proactively identify, assess, and mitigate risks, including security risks, throughout the software development lifecycle.
• Contribute to the evolution of CI/CD pipelines, improving automation and deployment processes.

Skills & Experience

• 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 a strong understanding of object-oriented design principles and software architecture.
• Deep understanding of the Software Development Life Cycle (SDLC) and agile methodologies.
• Experience with relational databases (e.g., MySQL, SQL Server, Oracle) and optimizing database interactions.
• Strong knowledge of security best practices, including secure coding principles and compliance requirements (e.g., OWASP Top Ten, PCI, SOC2, HIPAA).
• Proficient in networking concepts such as sockets, HTTPS, DNS, and SSL.
• Deep knowledge of design patterns and their practical application.
• Proven ability to work independently while also fostering teamwork and cross-team collaboration.
• Demonstrated ability to mentor junior engineers and contribute to the growth of the engineering team.
• Strong problem-solving skills, with the ability to anticipate potential issues and proactively address them.
• Excellent communication skills, capable of explaining complex technical concepts to both technical and non-technical stakeholders.

Benefits

• 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).
• Private medical insurance (upon 30 days of employment).
• 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.
• Bike2Work 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 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.

Please be aware that all offers of employment are made subject to receipt of satisfactory background and financial checks.

About us: NMI enables our partners with choice, and challenges the one-size-fits-all approach to payments. 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. We’re all about enabling more payments in more ways and more places.

Please note that in compliance with the data protection regulations within your jurisdiction, any personal information submitted with your job application may be collected and used by NMI for the purpose of recruitment and employment-related activities. By submitting your application, you acknowledge and provide explicit consent to the processing of your personal information as described in our privacy policy found on our website.