Senior Software Engineer

NMI

Senior Software Engineer developing and maintaining payment solutions for NMI. Joining a team focused on SDKs and backend components for secure transaction processing.

Posted 6/8/2026full-timeRemote • 🇬🇧 United KingdomSenior💰 £48,000 - £58,000 per yearWebsite

Tech Stack

Tools & technologies

DNSJavaMySQLOracleSDLCSQL

About the role

Key responsibilities & impact

Design, develop, and maintain secure, scalable, high-quality SDKs and backend services used in payment device integrations.
Lead architectural and design discussions across backend and mobile platforms.
Write and review well-structured, maintainable, and efficient code.
Collaborate closely with Product, QA, and Operations to ensure successful feature delivery.
Mentor junior and mid-level engineers, sharing best practices and guiding technical growth.
Participate in the evolution of CI/CD pipelines and deployment automation.
Ensure that all code and systems adhere to strong security and compliance requirements (e.g., PCI, OWASP).
Investigate and resolve performance issues across SDKs and backend services.
Contribute to cross-team initiatives, including SDK standardization and shared libraries.
Join the team’s out-of-hours on-call rota to support critical product alerts.

Requirements

What you’ll need

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

Comp & perks

Annual bonus scheme dependent on individual and company performance
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 that offers wellbeing, family and financial support services
A strong commitment to employee wellbeing including mental health first aiders
Employee referral scheme with generous financial reward
Bonusly colleague reward scheme

ATS Keywords

✓ Tailor your resume

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills & Tools

C#Javaobject-oriented designSoftware Development Life Cycle (SDLC)agile methodologiesMySQLSQL ServerOraclesecure coding principlesdesign patterns

Soft Skills

mentoringteamworkcross-team collaborationproblem-solvingcommunication