FinWise
Personal Finance Dashboard
FinWise is a personal finance management platform giving users a real-time, unified view of their financial life. Built with React and TypeScript on a Node.js backend, it integrates with 11,000+ financial institutions via Plaid, and features intelligent budgeting rules, automated savings triggers and multi-currency net worth tracking.
The Challenge
Aggregating financial data reliably from hundreds of different bank formats and APIs while maintaining user trust — especially around data security and privacy — is one of the harder engineering challenges in consumer software. The client also needed a UX simple enough for non-technical users, despite the underlying complexity.
- Plaid webhook reliability and error handling for 11,000+ institutions
- Normalising wildly inconsistent transaction category data across banks
- PCI DSS-aligned security architecture without becoming the data custodian
- Dashboard performance with 24+ months of historical transaction data
- Intelligent categorisation that learns from user corrections
Our Solution
We built on React 18 with TanStack Query for efficient server-state management and virtual lists for 24-month transaction data. Plaid Link handled institution connections. Webhooks drove real-time balance updates through a Node.js event processor. A custom ML categorisation layer (TensorFlow.js) adapted to each user's correction patterns without sending data to third-party AI APIs.
- React 18 + TypeScript with TanStack Query for optimistic, cached data fetching
- TanStack Virtual for 60fps scrolling through thousands of transactions
- Plaid Link + Webhooks for real-time account sync across 11,000+ institutions
- TensorFlow.js on-device categorisation that improves with user corrections
- PostgreSQL with table partitioning for sub-second queries on large datasets
- AES-256 encryption for all stored financial data; zero plaintext PII in logs
The Results
FinWise launched with strong word-of-mouth growth from its personal finance community beta. Within eight months: $2M+ in total assets tracked across 800+ active users, a dashboard load time consistently under one second, and a 94 NPS score — exceptionally high for a financial product. Plaid sync uptime held at 99.9% through multiple Plaid API incidents thanks to robust retry and fallback logic.
Technology Stack
Key Features & Capabilities
Bank Account Sync
Plaid integration connecting 11,000+ UK and US financial institutions with real-time balance updates via webhook-driven event processing.
Smart Budgets
Envelope budgeting with automatic category detection, rollover rules and proactive alerts before limits are hit — not after.
Automated Savings
Rule-based savings triggers: round-ups, fixed transfers and "save the difference" rules linked to spending patterns.
Multi-Currency Tracking
Real-time exchange rates for multi-currency portfolios with a unified GBP/USD net worth view and historical FX-adjusted charts.
Smart Categorisation
TensorFlow.js on-device categorisation that learns from corrections — getting more accurate over time without sharing data externally.
Reports & Tax Export
Annual spending summaries, category trend reports and CSV/PDF export formatted for accountant and self-assessment tax submission.
"FinWise is the most technically demanding product we've built, and Code Zerra handled every complexity — Plaid reliability, transaction normalisation, ML categorisation — with impressive calm and skill. Our users notice the polish in every interaction."
Daniel Kwon
CEO, FinWise Technologies