Software Engineer I in London

NMI is a leading provider of payment gateway solutions, specialising in card-present solutions and payment processing. Our innovative technologies empower businesses to securely accept payments and optimise 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 a Software Engineer I to join our Payments Processing group. This group develops and maintains world-class payment solutions, including PIN pad and card reader integration, mobile SDKs, and processor/acquirer connectivity. This is an excellent opportunity for an early-career engineer to work on real-world, production systems in the payments space while developing strong technical foundations in secure and reliable software development.

The ideal candidate is a motivated and capable software engineer with a solid foundation in software development and a strong desire to learn and grow. You may have experience in one or more of the following areas:

• Backend development (C#/.NET)
• Mobile development for Android (Java/Kotlin) or iOS (Objective-C/Swift)

You are comfortable working on well-defined tasks, contributing to team discussions, and developing your skills in building secure and reliable systems. You take pride in writing clean, maintainable code and are eager to learn best practices in software design, testing, and deployment. You work well within a team environment and are open to feedback and mentorship from more experienced engineers.

Key Responsibilities

• Develop and maintain secure, high-quality SDKs and backend services under the guidance of senior engineers.
• Write clean, well-structured, and maintainable code following established engineering standards.
• Participate in code reviews and incorporate feedback to improve quality and consistency.
• Collaborate with Product, QA, and other engineers to deliver features and resolve defects.
• Assist in debugging, troubleshooting, and resolving issues in SDKs and backend services.
• Contribute to testing efforts, including unit and integration testing.
• Follow security and compliance guidelines (e.g., OWASP, PCI) in all development work.
• Participate in team ceremonies and contribute to continuous improvement initiatives.
• Join the team's out-of-hours on-call rota after an onboarding period, with appropriate support and compensation provided.

Skills & Experience

• Bachelor's degree in Computer Science, Information Technology, or equivalent practical experience.
• 0–2 years of professional software development experience (including internships or placements).
• Proficiency in at least one object-oriented programming language (e.g., C#, Java, Kotlin, Swift).
• Solid understanding of object-oriented programming principles and basic design patterns.
• Familiarity with the Software Development Life Cycle (SDLC) and agile methodologies.
• Basic understanding of relational databases (e.g., MySQL, SQL Server, Oracle).
• Awareness of secure coding practices and common web/application security concepts (e.g., OWASP Top Ten).
• Basic understanding of networking fundamentals (e.g., HTTPS, DNS, SSL).
• Strong problem-solving skills and a willingness to learn from feedback.
• Good communication skills and the ability to collaborate effectively within a team.

Benefits

• Annual bonus scheme dependent on individual and company performance.
• Annual salary of £30,000 - £35,000.
• 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.
• 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'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.

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

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 realising it. We're the platform that powers success for innovative tech created by SMBs, entrepreneurs and fintech start-ups. 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 democratise the latest payments technology so that everyone can realise the benefits of easy payments across the full spectrum of commerce. 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.