At a Glance
- Tasks: Lead the development of .NET microservices and ensure high engineering standards.
- Company: Join a dynamic payments business with a focus on innovation and security.
- Benefits: Competitive salary, flexible working options, and opportunities for professional growth.
- Other info: Mentorship opportunities and a chance to shape the future of our engineering team.
- Why this job: Make a real impact in fintech by building secure and resilient payment systems.
- Qualifications: Extensive experience in C#/.NET, API design, and back-end system development.
The predicted salary is between 63000 - 77000 £ per year.
We are looking for a Senior Back-End Developer to become the technical anchor of our newly forming in-house engineering team. Our platform is built on a suite of .NET microservices, backed by PostgreSQL and Redis, running on Google Cloud Platform (GKE) and delivered through GitLab CI/CD. You will take deep ownership of this codebase: leading its ongoing development, raising engineering standards, and guiding the work of other developers as the in-house team grows. This is a senior, high-influence role in a regulated payments business. The services you build and harden move real money; correctness, resilience, and security are not nice-to-haves here, they are the job.
Key Responsibilities
- Lead the design, development, and maintenance of our .NET microservices, from API design through to data modelling and integration.
- Take ownership of the codebase: drive code quality, architectural coherence, and technical debt reduction across services.
- Design robust, well-tested services for payments, FX, and treasury workflows, with strong attention to correctness, idempotency, and auditability.
- Work with PostgreSQL and Redis for transactional data and caching, with an eye on performance and integrity.
- Contribute to and improve GitLab CI/CD pipelines, including automated testing, quality gates, and safe release practices.
- Mentor and review the work of other developers, in-house and external, setting the bar for engineering standards.
- Collaborate with our DevOps function on observability, reliability, and secure deployment onto GKE.
- Build with security and regulatory expectations in mind, and support audit and banking partner requests with technical input where needed.
Our Expectations
- Extensive commercial experience building production back-end systems in C# / .NET, including microservice architectures.
- Strong API design skills (REST) and experience with inter-service communication patterns, messaging, and resilience techniques.
- Deep working knowledge of PostgreSQL (schema design, query performance, transactions) and practical experience with Redis.
- Experience running containerised services in Kubernetes; GKE experience is a plus.
- Solid grounding in automated testing and CI/CD; GitLab experience is advantageous.
- A track record of leading by example: raising standards through code review, mentoring, and pragmatic technical leadership.
- Experience in payments, fintech, or another regulated environment is strongly advantageous.
- Clear communication skills and the judgement to make sound technical decisions in a small, fast-moving team.
Senior Back-End Developer (.NET) in London employer: Mark Loucas
Join a leading global payments and fintech business that values innovation and excellence, offering a dynamic work culture in London/Essex. As a Senior Technical Programme Manager, you will benefit from a collaborative environment that fosters professional growth and provides opportunities to lead impactful projects. With a focus on employee development and a commitment to work-life balance, this company stands out as an exceptional employer for those seeking meaningful and rewarding careers.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Back-End Developer (.NET) in London
✨Join Local Tech Meetups
Get out there and mingle with fellow developers by joining local tech meetups. It’s a fantastic way to meet people who might be working at Mark Loucas or know someone who does. Plus, you can pick up some trendy tech skills and trends while you're at it!
✨Contribute to Open Source Projects
Show off your coding chops by jumping into open-source projects. Not only does this give you practical experience, but it also gets you noticed in the dev community. You'll create a killer portfolio that speaks volumes about your skills to Mark Loucas.
✨Tap into Online Developer Communities
Don’t underestimate the power of online developer communities like GitHub, Stack Overflow, and even Reddit. Participate in discussions, share your projects, and build your visibility. We can often find opportunities through these channels that can lead to a full-time gig at companies like Mark Loucas.
✨Explore Job Boards Specifically for Tech Roles
Keep your eyes peeled on job boards that focus on tech roles. Sites like TechCareers or Stack Overflow Jobs can often have listings for companies like Mark Loucas that might not show up on broader job sites. Make it a habit to check these regularly, and don’t hesitate to apply directly through our website!
We think you need these skills to ace Senior Back-End Developer (.NET) in London
Some tips for your application 🫡
Show off your coding skills:When applying for a software engineering role, it's super important to showcase your coding skills. Make sure your CV includes your tech stack, any relevant programming languages you’re comfortable with, and examples of projects you've worked on. If you have a GitHub profile, link it up! We love to see code in action.
Tailor your portfolio:For a full-time role, we’d expect to see some solid examples of your work in your portfolio. Make sure to include at least two or three projects that highlight your problem-solving skills and your ability to work with different technologies. Focus on the projects that are most relevant to the position at Mark Loucas.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Mark Loucas and how your skills align with the role. Show us your passion for software development. We dig enthusiastic candidates who understand the value of collaboration and continuous learning!
Be clear and concise:When it comes to writing your CV and cover letter, clarity is key. Avoid jargon that could confuse us and stick to simple, direct language. Highlight your achievements with quantifiable results where possible, and keep everything easy to read. A well-organised application goes a long way!
How to prepare for a job interview at Mark Loucas
✨Brush Up on Your Coding Skills
For a full-time software engineering role, it's crucial that we stay sharp with our coding abilities. Expect technical questions that might involve solving problems on the spot or discussing algorithms. Practise on platforms like LeetCode or HackerRank to get comfortable with the types of questions that often come up.
✨Know Your Tools and Frameworks
Make sure we’re well-acquainted with the tools and technologies listed in the job description. Familiarise ourselves with any specific frameworks or programming languages mentioned. If Mark Loucas uses React or Node.js, for instance, be ready to discuss how we’ve used them in previous projects or coursework.
✨Showcase Your Projects
Bring along a portfolio that highlights our best work. This could be code samples, GitHub repositories, or any side projects we’ve built. Make sure we can talk through our thought process for each project, especially the challenges we faced and how we solved them—this shows our problem-solving skills in action.
✨Prepare for Behavioural Questions
While technical skills are key, full-time positions also require cultural fit. Be ready to discuss our previous experiences and how we handle teamwork, conflict, and deadlines. Brush up on the STAR method—Situation, Task, Action, Result—to clearly articulate our past experiences when discussing how we've contributed to a team.
