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Delivering Tandem’s Cash ISA
Design Leadership • DesignOps • Stakeholder Management • Mobile App Design
In early 2025, Tandem needed to keep customers for longer. People were moving their money to competitors who offered better interest rates. To fix this, and to increase the company's value ahead of a planned sale, bank decided to launch a major new product: a Cash ISA. This case study explains how we built and launched it in just nine months, despite losing half of our team.
Company
Tandem Bank
Year
2025
Project Type
Mobile App
Team Size
3 Product Designers (incl. me)
The Challenge
Shortly after we started, the company cut costs. Our design team shrank from seven to four, losing key designers and our design system lead.
We had a strict nine-month window to design, test, and build a highly regulated banking product.
We faced scope creep, unclear initial requirements, and strong pushback from senior leadership (Director of Savings) on established UX best practices.
FCA (Consumer Duty) compliance and legacy infrastructure issues caused delays in copy approval and design system integration.
Design Process
Strategic Prioritisation & Streamlining
We streamlined the design to meet our strict deadline. We cut nice-to-have sensory experiences, focusing entirely on delivering core functionality and a reliable user experience.
Strategic Prioritisation & Streamlining
Rather than leaving users to their own devices, our strategy was to guide them actively through the product. We ensured they were fully informed at every step, providing answers before they even had to ask a question. This proactive, transparent approach was vital for building trust and meeting strict FCA Consumer Duty regulations.
Deep-Diving into Complex Journeys
We paid special attention to the most complicated processes: ISA-in transfers and product maturity. We deeply analysed and repeatedly user-tested these specific flows with our 3,000-strong "Testing Lab" to guarantee clarity, speed, and effectiveness.
Data-Driven Stakeholder Alignment
We used research data to resolve internal debates and protect the user experience. When senior managers pushed for own solutions, we presented user data proving that our approach saved time and reduced friction, successfully securing their buy-in.
A Bulletproof Developer Handover
To prevent delays, we completely overhauled our engineering process. We created a single source of truth in Figma, linked directly to Jira, and centralised all communication. Crucially, every final design included written notes explaining the business and user goals, so developers and managers fully understood the why behind our decisions.
The Outcome
The Cash ISA launched to the market in November 2025.
The product was a huge success. It helped keep customers at the bank and directly supported Tandem’s goal of a future sale.
We successfully delivered a major banking product despite losing half our team, proving that our new ways of working were effective.
What I Have Learnt or Improved on
Improved presentation method to persuade senior managers - linking design choices back to business goals.
Keeping clear notes of meetings and decisions is vital. Relying on memory confuses later on.
Clear communication and strict handover processes are not just nice extras; they are essential when your team is stretched thin.
This project showed I can keep a clear head, guide a team, and deliver high-quality work even in difficult situations.
