Mobile and Backend Software Engineer - Banking

We’re Capital on Tap 👋💳 Capital on Tap started because small businesses were underserved. Big banks were slow, their products weren't fit for purpose, and small business owners often couldn't access what they needed. We set out to fix that.

Today we're a financial platform - not just a credit card company. We offer a best-in-class business credit card, SME-focused spend management platform, a savings product that hit £1 billion in funds within its first year, and a growing suite of tools and financial products that make running a small business easier.

1,000+ employees, £20bn in annual card spend, 200,000+ customers, 17,000+ Trustpilot reviews averaging 4.7 stars, and we're profitable. We’ve done a pretty good job so far, but we’re just getting started!

🏡🏢This is a Hybrid role, the team work from our London Offices 2 days per week.

The Team

The Banking and Repayments teams sit at the heart of Capital on Tap's product, owning the core account experience for thousands of small business customers. Banking manages account operations, transaction lifecycles, balance management, ClearBank integration, and savings. Repayments owns the repayment rails, including the most recent open banking repayments.

We value engineers who take genuine ownership, work autonomously, and bring depth across the stack. This is a high-priority hire with real impact from day one.

What You'll Be Doing

As a Senior mobile and backend Software Engineer, you'll own the back-end systems that power our Banking and Repayments platform , while also contributing to mobile - helping transition mobile and front-end ownership from our Customer Experience team into Banking.

• Design and build robust, scalable back-end services in C#/.NET
• Own the full SDLC - from feature inception through to production, monitoring, and continuous improvement
• Contribute to mobile development across iOS and Android using Flutter, Kotlin, and/or Swift
• Collaborate with Product, Design, and QA from early feature shaping through to delivery
• Write thorough unit and integration tests and uphold high engineering standards
• Identify bottlenecks and drive improvements across the team
• Work cross-functionally, bridging technical decisions with business goals

What We're Looking For

• Mobile development experience in Flutter/Dart, Kotlin, or Swift - this is a firm requirement

• Strong back-end engineering experience, ideally in C#/.NET

• Solid testing practice across unit and integration testing

• Experience with CI/CD platforms such as CodeMagic or similar

• Comfortable working in Agile environments

• Autonomous and collaborative - you take ownership and see things through

Our Tech Stack

• Backend: C#, .NET, .NET Core
• Mobile: Flutter, Dart, Riverpod, GoRouter, Kotlin, Swift
• Databases: SQL Server, MongoDB, Firestore
• Cloud: GCP (Firebase) and Azure
• CI/CD: CodeMagic

Diversity & Inclusion 🌈

We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.

Great Work Deserves Great Perks

We try not to take ourselves too seriously (all the time) so we make sure our office is decked out with a pool table, arcade machine, beer tap, and a couple of office dogs thrown in for good measure. Check out our benefits:

🏥 Private Healthcare including dental and opticians services through Vitality

✈️ Worldwide travel insurance through Vitality

🎁 Anniversary Rewards (£250, £500, £750, 4-week fully paid sabbatical)

👛 Salary Sacrifice Pension Scheme up to 7% match

🚘 Octopus EV Salary Sacrifice Scheme

🏖️ 28 days holiday (plus bank holidays)

📖 Annual Learning and Wellbeing Budget

👪 Enhanced Parental Leave

🚲 Cycle to Work Scheme

🚂 Season Ticket Loan

💬 6 free therapy sessions per year

🐶 Dog Friendly Offices

🍫 Free drinks and snacks in our offices

Check out more of our benefits, values and mission here.

Other Info 👍Check out our ‘Top Tips’ for interviewing.

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📧Email [email protected] if you have any questions.

**Excited to work here? Apply!**If you’d like to progress your career within our fast growing, profitable fintech then click apply and we will aim to get back to you within 3 working days (during busy periods this could take up to 5 working days.)