At a Glance
- Tasks: Design and develop scalable payment systems while mentoring engineering teams.
- Company: High-growth SaaS scale-up revolutionising money transfer and payments.
- Benefits: Flexible hours, competitive salary, 33 days holiday, and remote work options.
- Other info: Opportunity for clear career progression in a fast-paced environment.
- Why this job: Join a dynamic team shaping the future of FinTech with real impact.
- Qualifications: Experience in high-volume financial systems and strong architectural skills.
The predicted salary is between 80000 - 100000 £ per year.
Location: Hybrid – London (1–2 days per month)
Team: Core Engineering Team – Agile / Kanban
Overview
Our client is a high-growth SaaS scale-up transforming the world of money transfer and payments. Following consistent year-on-year revenue growth and successful funding, the business is entering its next phase of international expansion. To support this growth, they are seeking a Principal Engineer / Architect to join their Core Engineering Team—someone with strong architectural capability, but who remains highly hands-on in development. This role is ideal for a senior technologist who can design and shape scalable platform architecture while still being deeply involved in coding, engineering delivery, and solving complex technical problems. You will play a key role in scaling a modern platform that supports high-volume, real-time payments and financial transactions across a rapidly expanding global customer base. We are specifically looking for someone with proven experience building high-transaction financial systems, including payments, banking, money transfer, or regulated FinTech platforms.
The Role
As Principal Engineer / Architect, you will work closely with the CTO and senior leadership team to define technical strategy, platform architecture, and engineering best practice across the business. You will take ownership of designing scalable, secure, high-performance systems while also remaining hands-on in the delivery of key services and complex engineering challenges. This is not a pure architecture role—we need someone who still enjoys writing production-grade code, mentoring engineering teams, and leading from the front technically. The engineering team operates using a Kanban-based Agile model with continuous delivery, enabling rapid iteration and deployment of new features. This role suits someone who can balance strategic architecture with practical delivery and has operated successfully within fast-paced, high-growth FinTech or payments environments.
Key Responsibilities
- Architect and enhance .NET Core 9/10 applications and microservices supporting real-time payment processing
- Design secure, scalable, low-latency backend architectures for high-volume financial transaction platforms
- Lead technical decisions across API-led distributed systems and event-driven architecture
- Build and scale integrations supporting money transfers, card payments, savings functionality, and Mastercard integration
- Work across a modern Azure SaaS stack including:
- Improve platform resilience, observability, scalability, and operational excellence
- Collaborate closely with Operations to improve automation and reduce third-line support overhead
- Contribute to BAU operational tickets where required (~10–15%)
- Mentor senior developers and help elevate engineering standards across the team
- Support the CTO in defining long-term technical strategy and platform evolution
- Operate within a Kanban-based Agile environment focused on continuous delivery
Required Experience
- Proven experience operating at Principal Engineer, Lead Developer, or Solution Architect level while remaining hands-on
- Strong architectural design experience across distributed systems and microservices
- Proven experience working with high-volume OLTP systems
- Strong background building low-latency, real-time payment, banking, financial services, or money transfer platforms
- Strong MS SQL expertise and relational database design knowledge
- Experience with event-driven systems and asynchronous processing patterns
- Agile / Kanban development experience with a continuous delivery mindset
- Strong experience using Azure DevOps and Git
- Angular front-end development
- Infrastructure as Code (IaC) on Azure
- Experience working within SOC 2 or ISO 27001 environments
- Experience within software consultancies, software houses, or distributed international development teams
- Experience leading architecture reviews, technical governance, and engineering standards
What’s on Offer
- Flexible working hours and hybrid working
- Competitive salary, bonus, share scheme and benefits
- 33 days holiday (including bank holidays)
- Company laptop, PC or Mac (with Parallels)
- Rewards scheme with discounts across retail, hospitality, services and much more
- Expenses covered for travel/events
- The opportunity to work from anywhere – including up to 4 weeks abroad each year
- Clear career progression in a rapidly growing business
- The chance to work and collaborate with a team featuring a number of former consulting professionals
If you’re interested in building scalable FinTech platforms and shaping architecture within a high-growth SaaS environment, we’d love to hear from you. Unfortunately, our client are unable to provide sponsorship for this role.
Our client is committed to promoting Diversity, Equity, and Inclusion across all areas of their business. They strive to ensure fair and inclusive hiring practices that reduce bias, widen talent pools, and create opportunities based on skills, potential, and values. They believe that diverse teams create stronger businesses, better decision-making, and long-term success.
Principal Software Engineer in London employer: Focused Futures Consultancy LTD
Join a dynamic and innovative SaaS scale-up in London, where you'll have the opportunity to shape the future of money transfer and payments. With a strong focus on employee growth, flexible working arrangements, and a collaborative culture, this company offers competitive salaries, generous holiday allowances, and the chance to work with a talented team of professionals. Embrace the challenge of building scalable FinTech platforms while enjoying the benefits of a supportive environment that values diversity and inclusion.
Contact Details:
Focused Futures Consultancy LTD Recruitment Team
StudySmarter Expert Advice🤫
We think this is how you could land Principal Software Engineer 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 Focused Futures Consultancy LTD 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
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We think you need these skills to ace Principal Software Engineer 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 Focused Futures Consultancy LTD.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at Focused Futures Consultancy LTD 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 Focused Futures Consultancy LTD
✨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 Focused Futures Consultancy LTD 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.
