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Social economyApril 2026

L'Hermitage – Treasure Hunt

A mobile application (PWA) for the woodland estate of Tiers Lieu L'Hermitage. A playful, geolocated experience, installable on smartphones without app stores and working without a permanent connection.

4 weeks
Build time
Gamification
Active estate discovery
Mobile app
Native PWA

Project presentation

Tiers Lieu L'Hermitage — a tailor-made retreat venue for companies and gatherings, set in a woodland estate — wanted to give teams on corporate retreats a playful, interactive way to explore the grounds. The goal: a mobile treasure hunt that runs smoothly deep in the forest, with no app-store download and no dependency on a stable connection.

I built a Progressive Web App (PWA) with Next.js: no dedicated server, no account required. The app runs entirely on the visitor's smartphone and can be installed with a single tap from the browser onto the iOS or Android home screen, in full-screen mode like a native app.

The browser's native geolocation API triggers contextual riddles depending on where the players are in the estate. Progress and scores are persisted locally on the device (LocalStorage / IndexedDB) — the game stays playable offline and resumes exactly where it was left.

The game has been a hit, with stronger visitor engagement and a smooth, immediate user experience suited to outdoor use.

Objectives

  • Build a mobile application to explore the L'Hermitage woodland estate
  • Deliver a playful, geolocated and interactive experience for visitors
  • Enable store-free installation and offline operation

Results

  • Mobile app (PWA) installable without going through iOS / Android stores
  • Riddles triggered by the players' geolocation across the estate
  • Progress and scores persisted locally, offline operation
  • Retreat visitors actively engaged in exploring the estate
The technology trade-off
Options considered
  • — Native iOS/Android app published on the stores
  • — Classic mobile website used in the browser
  • — Progressive Web App (PWA), installable without stores
Decision

Next.js PWA, installable in one tap from the browser, no dedicated server.

Why this choice

Native meant the cost and delays of publishing on two stores for an event-driven use case; a classic website couldn't deliver full-screen mode or offline play deep in the forest. The PWA provides instant installation, native geolocation and local persistence (LocalStorage / IndexedDB) — the game keeps running without network.

“Thank you Agathe for the serious, creative work on the treasure hunt for the Tiers-Lieu L'Hermitage site. Co-creating this game with her was a pleasure — responsive, attentive and very efficient throughout. First test run with 120 people.”

Charlotte Bourez
Charlotte Bourez
Community café manager, L'Hermitage