Chooz, the Google Flights of European trains

Chooz is the Google Flights of European trains: a mobile app that compares train tickets on an interactive map, with price, duration and carbon footprint side by side.

Built in a team of four for a Demo Day in September 2025. I owned the design: Figma from wireframes to hi-fi, the design system, then its build in Bubble.

Stack: Bubble · Mapbox · Navitia and SNCF APIs · Google and Facebook login · Figma · Canva

Rail trips in Europe lack visibility, and booking an eco-friendly trip is complex: cluttered interfaces, intrusive ads, misleading prices and a fragmented offer.

Survey with 57 respondents and 3 qualitative interviews: price comes first, then duration, comfort and CO₂.

Two personas: Lysa, the eco-conscious traveller, and Marc, the pragmatic traveller.

How Might We: make search and booking simpler, put train routes and their carbon footprint forward, restore trust in prices.

Map-first comparison: destinations as price pins, routes drawn from the departure city, swipeable trip cards.

Theme filters (City Break, Nature, Playa, Deals) and sorting by price, duration or CO₂.

Trip details: legs, stations, onboard services and operators, then redirection to booking.

Booking in 3 steps, from user flow and user story map to low-fi sketches, wireframes, design system and high-fi prototype.

From moodboard and low-fi sketches drawn as a team, to wireframes and hi-fi mockups that I designed in Figma.

The Figma file, with components and hi-fi mockups:

The whole app design, from wireframes to hi-fi mockups and the clickable prototype, based on the low-fi sketches drawn with the team and our shared UX choices.

The design system: colours, typography, components, tags and states.

The design system rebuilt in Bubble: a dedicated page and 25+ reusable elements (buttons, inputs, date picker, dropdowns, search bar, map labels and filters, trip card, navigation).

Shared styles and 13 option sets (button labels, classes, currencies, FAQs, inputs, tags, traveller categories, trip types, map modes).

Custom states to hold temporary values on elements (selected filter, map mode, open popup), and conditionals for every element state: hover, pressed, focused, selected, disabled.

Animations and show/hide transitions on the interactive components.

Map integration with Mapbox: destination labels, routes and map controls (zoom, filters, list/map toggle).

Workflows for navigation between pages, the search popup, trip cards and map interactions.

The Demo Day pitch deck, embedded below.

Team: Bubble development and app architecture, database structure and APIs.

Architecture: Bubble for interface, logic and database, Navitia and SNCF APIs for real-time routes and timetables, Google and Facebook for authentication, Mapbox for the map.

P0 Demo Day MVP delivered. P1 price alerts, round trips and connections. P2 more operators (DB, Trenitalia), multi-currency, class and passenger filters.

The deck presented at Demo Day, designed in Canva:

The project as presented by Alegria Academy on LinkedIn: