Project Overview
A UK FinTech startup wanted to build a personal finance and budgeting app using Open Banking (TrueLayer AISP) ...
Technology Stack
Compliance & Standards
The Challenge
A UK FinTech startup wanted to build a personal finance and budgeting app using Open Banking (TrueLayer AISP) — providing automatic transaction categorisation, spending insights, and savings goals. FCA Consumer Duty (PS22/9 applied to apps providing regulated financial promotions), PECR, UK GDPR for financial transaction data, and ICO Guidance on Cookies and Similar Technologies were the requirements. The app needed to be functional before the founders' runway expired. Budget: £65,000.
Our Approach
TrueLayer AISP
OAuth 2.0 bank authorisation flow (22 UK banks supported at launch), 90-day consent re-authorisation handled automatically.
Transaction data
12 months history at connection, daily refresh thereafter.
Account types
current account, savings, credit card.
Transaction fields
amount, merchant, category (TrueLayer pre-categorised), timestamp, balance.
ML Transaction Categorisation
- TrueLayer provides basic categories.
- Custom ML layer for UK-specific categorisation accuracy: fine-tuned classification model (scikit-learn, trained on 180,000 anonymised UK transactions).
Categories
groceries (Tesco, Sainsbury's, Waitrose — merchant matching), bills (direct debit pattern detection), entertainment, dining, transport, NHS prescription (£9.90 flat amount), council tax (monthly round number), subscription (recurring monthly same merchant).
FCA Consumer Duty for Financial Apps
FCA Consumer Duty applies to apps providing financial promotions.
Savings products promotion
must be FCA-compliant, fair, clear, and not misleading.
Consumer Understanding
all financial terms explained (APR, AER, cashback — not assumed known).
Vulnerability indicators
unusual spending patterns (consistent overdraft, missed bill payments) trigger in-app support signpost — not automated advice (that would require FCA authorisation).
React Native App and UK GDPR
- React Native (iOS + Android) with minimal permissions request.
- UK GDPR explicit consent for Open Banking data processing.
Data minimisation
only transaction data used for categorisation and budgeting — no location, no contacts, no camera unless user initiates photo upload.
Right to erasure
immediate revocation of all bank connections via TrueLayer API + deletion of all transaction data within 24 hours.
The Results
App launched in App Store and Play Store at 13 weeks, £60,000 — under budget. 18,400 registered users in first 6 months (organic, no paid acquisition).
Open Banking connections: 14,200 active connections.
Transaction categorisation accuracy: 94.2% (TrueLayer baseline: 78%).
FCA Consumer Duty: financial promotions reviewed and cleared by compliance consultants.
ICO PECR cookie audit: zero findings.
App Store rating: 4.7/5.
“£60,000 and 13 weeks to an App Store launch — that is the MVP build we needed to raise our seed round. 18,400 organic users in 6 months validated the product. The 94% categorisation accuracy versus TrueLayer's 78% baseline is a real product differentiator that investors understood immediately." — CEO, UK Personal Finance FinTech (name withheld)”
Project Details
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