Senior Software Engineer

IFX Payments; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

A leading fintech company in Greater London is seeking a Senior Backend Engineer to design and implement robust, scalable backend solutions. The successful candidate will leverage extensive experience in C# and .NET to develop high-performance, secure RESTful APIs. You will work closely with cross-functional teams, mentor junior developers, and contribute to architectural decisions. Competitive holiday benefits and a commitment to employee well-being are offered, including a strong focus on continuous professional development and a vibrant company culture.

Benefits

25 days' annual leave plus bank holidays

Life Insurance

Career development tools

Work abroad scheme

Enhanced parental leave

Qualifications

• Significant experience as a senior C# developer with .NET Core 6+.
• Proficiency in designing and developing secure and performant RESTful APIs.
• Experience with continuous integration / delivery methodologies.

Responsibilities

• Design, develop, and maintain secure RESTful APIs.
• Collaborate with cross-functional teams.
• Participate in code reviews and mentor junior developers.

Skills

C#

RESTful APIs

SQL Server

Agile methodologies

Git

Docker

Education

Bachelor's or Master's degree in Computer Science, Engineering, or related field

Tools

Azure DevOps

Entity Framework Core

RabbitMQ

Kafka

Job description

Description

We are looking for a highly skilled Senior Backend Engineer to join our growing engineering team. The ideal candidate will have extensive experience with C# and a passion for creating robust, scalable backend solutions. In this role, you will design and implement high-performance systems for our fintech platform, making use of your expertise in .NET, database optimisation, and API design. If you are a problem-solver who thrives on technical challenges and wants to help shape the future of financial technology, we want to hear from you.

Key Responsibilities

• Design, develop, and maintain secure and performant RESTful APIs using C# and .NET 6 / 7.
• Work on both green-field and brown-field projects utilizing .NET and .NET Core technology stacks.
• Collaborate with cross-functional teams to deliver high-quality software solutions.
• Participate in code reviews and mentor junior developers.
• Contribute to architectural decisions and best practices.
• Implement and maintain continuous integration / delivery pipelines.
• Ensure code quality, performance, and scalability.
• Participate in the design and implementation of microservices architecture.
• Optimise database performance and query efficiency.

Skills, Knowledge & Expertise

• Bachelor's or Master's degree in Computer Science, Engineering, or a related field.
• Significant experience as a senior C# developer with .NET Core 6+.
• Proficiency in designing and developing secure and performant RESTful APIs.
• Experience with methodologies and frameworks (e.g. xUnit, Nunit, K6, or similar frameworks).
• Strong understanding of software development principles in backend or full-stack environments.
• Experience working in Agile environments and delivering high-quality code within tight deadlines.
• Excellent problem-solving skills and the ability to work independently and as part of a team.
• Advanced knowledge of distributed, asynchronous event-driven systems.
• Up-to-date knowledge of continuous integration / delivery methodologies and build pipelines (e.g., Azure DevOps, Jenkins).
• In-depth knowledge of repository management, version control, branching, and merging with Git.
• Proficiency with SQL Server and experience optimising complex queries.
• Familiarity with ORMs such as Entity Framework Core or Dapper.
• Experience with message queues or event streaming platforms (e.g., RabbitMQ, Kafka).
• Excellent communication skills and the ability to interact effectively with various stakeholders.
• Strong analytical and strategic thinking skills.
• Product engineering and value delivery mindset.
• Customer-centric approach to product development.

Job Benefits

• 25 days' annual leave, plus bank holidays and an extra day off for your birthday!
• Holiday loyalty scheme.
• Life Insurance.
• Work abroad scheme.
• Enrolment into our pension scheme, which we offer via a salary exchange scheme.
• Access to a financial education, planning and coaching platform.
• Membership with Healthcare platform, which offers cash back on healthcare focused on dental, optical & physio, plus access to stress helplines, a virtual GP and more.
• Salary exchange nursery fees.
• Enhanced parental leave.
• Cycle to work.
• Career development and progression tools.
• Company events – Sporting events, pub nights, seasonal parties, socials.

We're an award-winning global provider of foreign exchange and payment solutions. On a mission to become the number one service-led alternative banking partner in EMEA for corporates and Financial Institutions that add value beyond the transaction.

FX Payments was built to challenge the status quo of cross-border money movement. From our early days to today, our goal has remained the same: to provide seamless, secure, and scalable solutions for businesses operating globally. With a growing presence and a reputation for service excellence, we've become a trusted partner for clients who demand more from their payment provider. We're here to make international money movement feel local—driven by service, powered by innovation, and committed to delivering value beyond the transaction.