MumSense

MumSense helps busy mums save money on groceries with AI receipt scanning, in-store price checks, community deals, and bite-sized investing lessons , all in one app.

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Inspiration

The inspiration for MumSense came from a painfully relatable moment: standing in a supermarket aisle, staring at a price tag, and thinking "is this actually a good deal?"

For busy mums, the weekly grocery shop is one of the biggest recurring household expenses. Studies show the average family overspends by 15% or more, not because they're careless, but because they simply don't have time to compare prices, track spending patterns, or research alternatives. And when it comes to building long-term wealth, most financial apps feel intimidating, jargon-heavy, and designed for people who already have money to invest.

We wanted to build the opposite: a single app where a mum can price-check a product while standing in the store, scan her receipt on the way home, get AI-powered savings tips that evening, and learn investing basics during her 10-minute coffee break. Financial confidence shouldn't require a finance degree.

What it does

MumSense is a mobile app that helps busy mums save money on everyday shopping and learn to grow what they save.

  • In-Store Price Check - Scan or type any product while shopping. MumSense instantly compares prices across nearby stores and ranks them cheapest to most expensive, so you know before you reach the till.
  • AI Receipt Scanning - Snap a photo of any receipt. AI extracts every item, the store, quantities, and the total automatically. One scan and MumSense starts learning what you buy.
  • Smart Insights - See spending breakdowns by category, store, and day. Get personalised "Swap & Save" suggestions, trend alerts, and bulk buy recommendations based on your actual purchase history.
  • AI Budget Coach - A conversational AI that analyses your receipts and gives step-by-step plans to reduce your grocery bill. Ask it "How do I cut my weekly shop to under £60?" and it gives specific items, stores, and savings.
  • Community Trolleys, Deals & Bulk Buys - Browse real shopping trolleys shared by other mums, discover live local deals verified by the community, and join group bulk purchases for wholesale prices.
  • Learn to Invest (Grow) - AI generates fresh bite-sized investing lessons every day, tailored to your experience level and country. A practice portfolio lets you trade with simulated money and get AI feedback on every decision. An AI investment coach provides personalised guidance based on your goals and risk tolerance.

How we built it

We built MumSense as a full-stack mobile application with AI at every layer, designed to feel native and fast.

Mobile App

React Native with Expo (TypeScript). We chose Expo for rapid cross-platform development and OTA updates. The app uses React Navigation with a custom bottom tab bar and a hand-built design system using design tokens for consistent spacing, typography, and colour across 30+ screens.

Backend

NestJS (Node.js) with PostgreSQL (Supabase) and Prisma ORM. NestJS gave us a modular, testable architecture. Supabase handles auth and hosting. WebSocket support powers real-time community chat with typing indicators and online presence.

AI Engine

OpenAI GPT powers six distinct AI features:

  1. Receipt OCR - extracts structured data from messy receipt photos
  2. Smart Insights - analyses spending patterns and generates personalised swap/save recommendations
  3. Budget Coach - conversational AI that builds custom savings plans from your receipt history
  4. Price Comparison - finds cheaper alternatives across stores for any product
  5. Daily Lesson Generation - creates fresh, country-specific investing lessons every day
  6. Investment Coach - personalised guidance based on risk profile, goals, and local regulations

Subscriptions

RevenueCat manages a freemium model with free trial, monthly ($4.99), and annual ($39.99) plans. Free users get 1 receipt scan and 1 AI chat per week. Pro unlocks unlimited everything.

Notifications

Expo Push Notifications for deal alerts, insight reminders, bulk buy updates, and community activity.

Challenges we ran into

1. Receipt OCR in the Real World

Lab photos of receipts are clean. Real receipts are crumpled, faded, folded, and photographed at weird angles under fluorescent lighting. Our first pass had ~60% item extraction accuracy. We iterated extensively on prompt engineering, adding structured output schemas and multi-pass validation, to get reliable extraction across different store formats and countries.

2. Making Investing Feel Safe

The investing module was the hardest UX challenge. Our target user has likely never bought a stock. Words like "ETF", "portfolio allocation", and "risk tolerance" can feel intimidating. We solved this with three layers:

  • An onboarding flow that asks simple questions ("Do you have an emergency fund?") instead of financial jargon
  • A practice portfolio with simulated money so there's literally zero risk
  • AI feedback on every trade that explains why a decision was good or risky, in plain language

3. Global by Default

MumSense isn't tied to any country. All intelligence is learned from user data via AI rather than hardcoded store names or regional pricing. This sounds simple, but it meant every feature (price comparison, insights, lessons, currency formatting) had to be currency-agnostic and region-aware from Day 1.

4. Community Trust

User-submitted deals and trolleys need trust. We implemented a community verification system where members can upvote/verify deals, and trolleys show real receipt data rather than self-reported numbers.

Accomplishments that we're proud of

  • End-to-end flow in under 60 seconds: A user can open the app, scan a product, and see cheaper options at other stores before they've even finished their shop.
  • Six AI features, one coherent experience: Receipt scanning, insights, budget coaching, price checking, daily lessons, and investment coaching all feel like parts of one app, not bolted-on modules.
  • Community network effect: Shared trolleys, verified deals, and bulk buys mean the app gets more valuable as more mums join.
  • Investing for complete beginners: AI-generated daily lessons, a practice portfolio, and a personal coach make investing genuinely accessible to someone who's never bought a stock.

What we learned

  • Tools beat theory. Busy mums don't want a budgeting spreadsheet or a savings article. They want to point their phone at a product and know if they're getting ripped off. Build the tool, not the tutorial.
  • Personalisation drives action. Generic tips get ignored. "Switch from Brand X butter to Store Y own-brand and save £1.40/week" gets action. AI that knows your actual receipts changes the game.
  • Community builds trust faster than algorithms. Seeing that another mum near you fed a family of four for £55 at a specific store is more persuasive than any AI recommendation.

What's next for MumSense

  • Barcode scanning for instant in-store price lookup without typing
  • Meal planning integration to suggest weekly meal plans based on what's on sale nearby
  • Family accounts so multiple household members can contribute receipts
  • Regional expansion with localised store data and partnerships
  • Real brokerage integration so users can graduate from practice portfolios to real investing when they're ready

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