Backend Software Engineer C# .Net AWS

Client Server Ltd.; Bracknell; Hybrid; GBP 70,000 - 85,000; Full time

Benefits offered by this job

Bonus

Pension

Life Assurance

Income Protection

Critical Illness Cover

23 days holiday

Job summary

Client Server Ltd. is seeking a Senior Backend Engineer to join a major rebuild of a leading international payments platform in Bracknell.

You will work in a small autonomous team, delivering robust APIs and backend services with C# .NET Core while modernising existing systems and contributing to architectural evolution. You will design, implement and own features end-to-end, mentor peers, and collaborate across engineering to ensure production-grade delivery, with hybrid work between Bracknell

Qualifications

• Strong C# .NET Core backend development experience.
• Experience building production APIs.
• Good SQL skills.
• Experience with system design, software architecture, microservices and event-driven systems.
• Comfortable working with cloud infrastructure in production; AWS preferred.
• Experience mentoring engineers and sharing technical knowledge.
• Hands-on experience using AI coding tools such as Claude or Copilot.
• Finance/payments experience is desirable but not essential.

Responsibilities

• Design and implement robust, scalable APIs and backend services using C# .NET Core.
• Modernise existing services and contribute to the rebuild of the Corporate Payments platform.
• Lead delivery of new features and technical projects from design through to production.
• Apply system design and architectural principles, including microservices and event-driven architecture.
• Design and optimise SQL databases and queries.
• Write, maintain and improve automated tests, ensuring high quality.
• Work with AWS or other cloud platforms in production environments.
• Mentor other engineers and contribute to technical best practice.

Skills

C# .NET Core

API design

SQL

Microservices

Cloud (AWS)

Mentoring

AI tooling (Claude, Copilot)

Tools

GitHub Copilot

Claude

Job description

Bracknell, Berkshire | £70k - £85k per year

Backend Software Engineer / Developer (C# .Net API SQL) Bracknell / WFH to £85k

Opportunity for Senior Backend Engineer to join a major rebuild of a leading international payments platform, working within the Corporate Payments division.

As a Backend Software Engineer you'll join a small, autonomous engineering team of around 4-6, including QA and a Team Lead, helping to modernise backend services and build the next generation of the platform. This is a hands‑on role with genuine technical ownership, where you'll lead the delivery of new capabilities and contribute to the evolution of the underlying architecture.

Your role:

• Design and implement robust, scalable APIs and backend services using C# .Net Core
• Modernise existing services and contribute to the rebuild of the Corporate Payments platform
• Lead delivery of new features and technical projects from design through to production
• Apply system design and architectural principles, including microservices and event driven architecture
• Design and optimise SQL databases and queries
• Write, maintain and improve automated tests, ensuring high standards of quality
• Work with AWS or other cloud platforms in production environments
• Leverage AI development tools including Claude and GitHub Copilot to improve engineering productivity
• Mentor other engineers and contribute to technical best practice

Location / WFH:

You can work from home most of the time, joining colleagues in the Bracknell office twice a week.

About you:

• You have strong C# .Net Core backend development experience
• You have experience building production APIs
• You have good SQL skills
• You have experience with system design, software architecture, microservices and event driven systems
• You're comfortable working with cloud infrastructure in production; AWS preferred
• You have experience mentoring engineers and sharing technical knowledge
• You have hands‑on experience using AI coding / development tools such as Claude or Copilot
• Finance / payments experience is desirable, but not essential

What's in it for you:

• Salary to £85k + bonus
• 23 days holiday, rising to 28 + your birthday off
• Pension
• Life Assurance
• Income Protection
• Critical Illness Cover