At a Glance
- Tasks: Design and build core banking systems that power customer journeys.
- Company: Join a dynamic fintech startup on the path to UK banking licence.
- Benefits: Competitive salary, flexible working, and opportunities for professional growth.
- Other info: Collaborative environment with a focus on innovation and mentorship.
- Why this job: Make a real impact in fintech by building foundational systems.
- Qualifications: Experience in backend or full-stack engineering with Node.js and AWS.
The predicted salary is between 60750 - 74250 £ per year.
We're building the core banking capabilities that power everything at Onmo - the systems that hold accounts, move money, calculate interest and generate statements. The Core Systems team owns these capabilities end to end, along with the shared services the rest of engineering builds on. You’ll help build new core systems from the ground up as we grow and pursue a UK banking licence, evolve the services every team depends on, and set patterns that get adopted across engineering. Your work reaches customers through every journey at once.
TECH STACK
- Backend: Node.js / TypeScript on AWS - serverless (Lambda, API Gateway, DynamoDB, S3, SNS, SQS, EventBridge, Kinesis) and containerised compute (ECS, ECR, EC2), with more of the latter as our core systems grow
- Frontend: React / Next.js
- Infrastructure: Terraform, GitHub Actions CI/CD, Docker
- Observability: Datadog, Grafana, Prometheus, Loki
RESPONSIBILITIES
- Design, build and run core banking capabilities - money movement, interest, statements, reconciliation - that are accurate, monitored and dependable
- Build new core systems and migrate off vendors safely: parallel runs, reconciliation, clean cutovers
- Own and evolve our shared services: modernise patterns, improve reliability and performance, keep them easy to build on
- Set patterns that get adopted across engineering through our RFC process - landed as libraries, guides and paved paths, not one-off fixes
- Review other teams’ contributions to core‑owned services: quick, helpful reviews that keep the bar high without blocking anyone
- Write code that sets the standard - tested, correct, documented - and mentor engineers across the function
- Help shape technical direction with the tech lead: architecture, build-vs-buy decisions, engineering standards
- Make our systems self-serve, so other teams can ship on them without needing us
ABOUT YOU SKILLS / ATTRIBUTES
- You care about correctness - edge cases, idempotency, retries, reconciliation - because this code moves money
- You're comfortable designing distributed, event-driven systems and reasoning about failure modes and data consistency
- You'd rather build the paved path than fix the same problem five times, and you write things down so others can follow
- You communicate clearly with engineers, product and business stakeholders, and review others' work firmly and kindly
- You're pragmatic in a startup: happy across greenfield builds and a legacy estate mid-migration, choosing boring technology when boring is right
- You want real ownership of foundational systems
- Can operate effectively under ambiguity
QUALIFICATIONS / EXPERIENCE
- Proven experience as a senior backend or full-stack engineer building and running distributed systems in production
- Strong Node.js/TypeScript and AWS, across serverless and containerised workloads
- Infrastructure as code with Terraform; CI/CD as a habit
- A track record of raising engineering standards around you - through reviews, patterns, tooling or mentoring
- You write clean, tested, maintainable code and leave systems more understandable than you found them
BONUS SKILLS
- Fintech, banking, payments or ledger experience - reconciliation, card rails, double-entry accounting
- Experience with core system migrations or vendor replacements
- Experience getting real leverage from AI-assisted development tooling
- Start-up experience
FCA Compliance & Consumer Duty
At Onmo we all take collective responsibility for our individual roles in creating the best outcomes for our customers. In this role that involves:
- Following the FCA Conduct Rules:
- You must act with integrity
- You must act with due skill, care and diligence
- You must be open and cooperative with the FCA, PRA and other regulators
- You must pay due regard to the interests of customers and treat them fairly
- You must observe proper standards of market conduct
Senior Software Engineer - Core Systems employer: ONMO
Onmo is an exceptional employer that prioritises employee growth and development within a dynamic and supportive work culture. As a Financial Accountant, you will be part of a passionate team dedicated to empowering individuals in their financial journeys, while enjoying the benefits of a collaborative environment that encourages innovation and continuous improvement. Located in a vibrant area, Onmo offers unique opportunities for professional advancement and the chance to make a meaningful impact in the financial services sector.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Software Engineer - Core Systems
✨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 ONMO 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 ONMO.
✨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 ONMO.
✨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 ONMO 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 Software Engineer - Core Systems
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 ONMO.
Craft a killer cover letter:Your cover letter is your chance to stand out—make it personal! Explain why you want to work at ONMO 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 ONMO
✨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 ONMO 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.
