Principal Software Engineer C# .Net AWS - FinTech

Client Server Limited; Greater London; Hybrid; GBP 110,000 - 130,000; Full time

Benefits offered by this job

Bonus (c20%)

Pension (5% employer contribution)

25 days holiday (increasing to 27 then

Life Assurance (4x base salary)

Employee Assistance Programme

Training and career development

Impactful role on cutting edge tech

Job summary

Client Server Limited is seeking a Principal Software Engineer in London/Hybrid to architect and deliver scalable C#/.NET services on AWS, with optional Python work. You will influence product direction, champion best practices, and guide cross-functional teams in fast-paced sprints.

The role offers hybrid work with two days in the London office and two days remote. The ideal candidate has deep C#/.NET experience, AWS knowledge, and a track record delivering scalable fintech-style systems, with

Qualifications

• Strong knowledge of C# backend development and modern best practices.
• Experience with scalable systems and cloud deployment (AWS).
• Interest in AI/ML tooling and exploring ChatGPT, Claude, Copilot and related tech.

Responsibilities

• Architect and build highly performant, scalable solutions using the Microsoft tech stack.
• Collaborate with cross-functional Agile teams in 2-week sprints and promote best practices.
• Drive adoption of AI within the business, exploring bots and process improvements.
• Report to the CTO and provide technical leadership across projects.

Skills

C# / .NET

Python

AWS

Job description

Principal Software Engineer C# .Net AWS - FinTech

London, Greater London | £110k - £130k per year

Principal Software Engineer / Developer (C# .Net AWS Python) London / WFH to £130k

Would you like to join a growing and profitable scale-up that is viewed as a leading FinTech disruptor in a senior role that will allow you a great deal of influence and progression?

As a Principal Software Engineer you will architect and build highly performant and scalable solutions using the Microsoft tech stack and SOLID design principles, collaborating with cross functional Agile project teams in 2 week Sprints, you'll be an advocate of best practice and ensure software is delivered to schedule.

There's a host of new features and development work and you'll also help to drive the adoption of AI within the business, introducing things like chat bots and exploring the use of AI to make process improvements.

This is an impactful role where you'll report into and collaborate with the CTO, you'll have a lot of visibility and quickly see the results of your work.

Location / WFH:

There's a hybrid policy, with two days in the brand new London offices and flexibility to work from home two days a week (Thursdays and Fridays).

About you:

• You are an experienced Software Developer / Engineer with a strong knowledge of modern best practice
• You have strong C# backend development skills, ideally also Python coding skills
• You have good knowledge of AWS
• You have experience of working on highly scalable systems
• You have technical project leadership experience
• You have experience in a FinTech or start-up environmentYou have a strong knowledge of Computer Science fundamentals such as OOP, Data Structures, Design Patterns
• You have experience with, or a strong interest in Artificial Intelligence and are keen to explore the possibilities further e.g. ChatGPT, Claude, Cursor, Copilot
• You have strong analysis and problem solving skills alongside organisation and planning abilities
• You have business acumen and advanced communication / stakeholder management skills

What's in it for you:

As a Principal Software Engineer you will earn a competitive package including:

• Salary to £130k
• Bonus (c20%)
• Pension (5% employer contribution)
• 25 days holiday (increasing to 27 after two years and 30 after)
• Life Assurance (4x base salary)
• Employee Assistance Programme
• Range of training, career development and supported learning
• Impactful role working on cutting edge technology