Never lose a sale again.

Context

Cameroonian commerce happens on WhatsApp: the customer asks for photos, the seller sends them one by one, the customer says they’ll think about it — and everyone forgets. Sales aren’t lost because of a lack of demand, they’re lost because of a lack of follow-up. And accounting happens in a notebook, when it happens at all.

Next Sales turns that chaos into a system: the customer browses a professional online catalogue (no app to install), orders in one tap via WhatsApp, receives a compliant PDF invoice — and the app tells the shopkeeper who to follow up with, when, and with what message, already written, ready to send over WhatsApp.

My role

Design, mobile development in Flutter, web catalogue and admin back-office in Next.js, landing-page copywriting, launch and operations — a personal product end to end, monetised through Mobile Money subscriptions.

The product

Shareable online catalogue

• Custom URL: next-sales.pro/c/your-shop — accessible from any phone, no install needed;
• product pages with multiple photos, YouTube video, characteristics, moderated customer reviews;
• integrated WhatsApp button: order in one tap in the channel the customer already uses;
• full customisation: logo, banner, tagline, colour;
• synced stock: a product marked out of stock disappears from the catalogue instantly;
• view statistics (7 days, 30 days, total).

Compliant PDF invoices and quotes

• automatic sequential numbering (INV-2026-00001);
• Cameroonian legal mentions: RCCM, taxpayer number, configurable VAT;
• 2 templates (portrait simple, landscape detailed), quotes convertible to invoices after payment;
• direct WhatsApp sharing, full history per customer.

WhatsApp follow-ups — the differentiator

• follow-ups created automatically after every sale;
• 7 types: payment collection, delivery, restock, satisfaction, interest, stock alert, custom;
• pre-written messages with customer name, product and amount injected — zero friction between the reminder and the action;
• push notifications and tracked statuses (to do, done, postponed).

Stock, customers, dashboards

• real-time stock with threshold alerts, movement history, real margin (buy price vs sell price);
• Excel import for customers and products, phone contact import, barcode scanning;
• dashboard: revenue day/week/month, partial payments and outstanding balances, top products, top customers;
• multi-shop at no extra cost: one subscription, several outlets;
• offline mode with automatic sync when the network returns.

Structural decisions

The public catalogue as an app ↔ web bridge

The seller manages everything from their phone; their customers install nothing — they get a URL. This decoupling (private app / public synced storefront) is what makes the product viral: every catalogue link shared on WhatsApp is an ad for Next Sales.

Follow-ups as semi-assisted automation, not as spam

The app never messages customers on its own: it prepares everything (moment, message, recipient) and lets the seller tap. WhatsApp compliance preserved, human relationship maintained, friction reduced to one tap.

Pricing built for the market

2,500 FCFA/month — less than a restaurant meal — payable without a bank card via Mobile Money, with 30 days of full trial. The “taste everything, then decide” strategy.

Hybrid mobile + web architecture

Private Flutter/Riverpod app + public Next.js storefronts (SSR, SEO) + Next.js admin back-office — three clients, one Firebase source of truth. A stock rupture declared in the app instantly disappears from the catalogue.

What this project proves

• product-market fit on an informal market: digitising without distorting;
• full B2C SaaS solo: product, compliant invoicing, Mobile Money subscriptions, support, affiliate programme;
• proven monetisation: ~13 % conversion on a market where the freemium norm is under 2 %;
• growth engineering: product-led virality, SEO, educational blog, video demo;
• field reliability: offline-first, local PDF generation, Excel import.

The number that matters: ~13 % conversion to paid. In mobile freemium, converting 2 % of downloads to paid users is considered a success. Next Sales converts one in eight — proof that the product solves a problem Cameroonian shopkeepers are ready to pay for every month.