The client
Second-hand selling in Mauritius mostly happens in Facebook groups and WhatsApp chats, where buyers pay strangers up front and hope the item arrives. Coin des Bon Plans set out to give that market a proper home.
The problem
A marketplace between strangers only works if both sides feel safe: buyers need to know they will get what they paid for, and sellers need to know they will be paid.
Most Mauritians pay each other by MCB Juice or bank transfer rather than card, so the app had to handle those payments properly, without a card gateway.
What they needed
- Phone-number sign-up, with buyer and seller modes on the same account
- Listings with photos, sizes, brands and categories
- Search and filters, favourites and a cart
- Payment by MCB Juice or bank transfer, checked before an order proceeds
- Buyer protection, and seller payouts managed by the platform
- Chat between buyer and seller, and follow-up when deliveries run late
- Everything needed for App Store approval: terms, account deletion, reporting and blocking users
What we built
We built the app in React Native with a Firebase backend: phone authentication, Firestore, file storage for photos and payment proofs, push notifications and Cloud Functions.
At checkout the buyer pays by MCB Juice or bank transfer and uploads the payment proof with its reference. The order waits in a “verifying payment” state until the platform confirms it. A small Buyer Protection fee funds the service. Sellers pay no commission.
Sellers see their earnings in an in-app wallet with pending and available balances and request withdrawals, which the platform pays out. Scheduled functions follow every order: sellers are reminded when a delivery is overdue, and late orders are escalated to the admin team.
Delivered features
- Phone-number login, buyer and seller modes
- Personalised feed on first launch
- Listings with photos, size, brand and category
- Search with category, size and brand filters
- Favourites, cart and checkout with seller shipping fees
- MCB Juice / bank transfer with payment-proof upload
- Buyer Protection fee, no seller commission
- Seller wallet with withdrawals
- Real-time buyer–seller chat with push notifications
- Order tracking and overdue-delivery follow-up
- Report and block users, account deletion
- In-app admin: users, listings, orders, finance, FAQs
Challenges we solved
Local payments without a card gateway
Juice and bank transfers can’t be confirmed by an API, so the checkout collects a proof and reference and holds the order until it is verified. It is simple for buyers and safe for sellers.
Keeping orders moving
Daily scheduled checks remind sellers who have not shipped after four days and escalate the order to the admin team after five, so buyers are not left waiting.
Passing App Store review
User-generated marketplaces must let people report and block others and delete their accounts. These were built in, together with an end-user licence agreement.
The result
Coin des Bon Plans has been live on the App Store in Mauritius since April 2026, giving local buyers and sellers a dedicated marketplace with protected payments.