Demonstration project — fictional brand
Kassa
Payment-collection software for Mobile Money and tontines, with a real app to try.
Project sheetKAS
- Sector
- Finance and retail
- Market
- Cameroon and diaspora
- Type
- Website and app
- Pages
- 23
- Languages
- French, English (home page)
- Built in
- 2026
The need
A shopkeeper receives payments on three Mobile Money numbers and copies everything into a notebook every evening. A treasurer of a tontine (a savings circle) chases members spread between Yaoundé, Bamenda and Paris, and nobody agrees on the order of turns. Kassa gives them a single screen. The site has to prove one thing: Kassa never touches the money.
For their customers
When a customer pays, the payment shows up at once on the shopkeeper’s side and the receipt goes out by itself: no more screenshots to check. In the tontine, every member sees the same grid, and reminders stay polite.
What I built
-
An app that works
You sign in with a code received by SMS (simulated) and land on a dashboard: today’s takings, a 30-day curve by payment method, payments arriving live.
-
Tontines run without a notebook
Each tontine has its rotation wheel, its calendar and its grid of contributions. The treasurer reminds a late member with a polite message she can edit.
-
Honest pricing and calculator
Prices show in CFA francs or euros, monthly or yearly. The calculator compares the time saved with the cost. If Kassa isn’t worth it, it says so.
Design choices
An accountant’s ledger at night: dark background, figures in a monospaced font. Lemon marks money coming in, purple the tontine circle. A light theme is available.
- Onest for headings and text
- JetBrains Mono for amounts
- NightBackground#0A0D16
- LemonMoney coming in#C6F24E
- PurpleTontines#9B7EFF
- CoralLate payments#FF8A75
Measurements
Home page of the demo, on mobile and on desktop.
| Metric | Mobile | Desktop |
|---|---|---|
| Performance | 99 | 100 |
| Accessibility | 100 | 100 |
| Best practices | 100 | 100 |
| SEO | 100 | 100 |
| Largest Contentful Paint (LCP) | 1,719 ms | 450 ms |
| Transferred size | 148 KB | 142 KB |
Measured on 3 October 2026 with Lighthouse 13 (default profiles), page served compressed from a local server, as in production.
Built with AI
Design, art direction and checks by me. Code and content produced in collaboration with AI agents, then reviewed and tested.
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Mike SOBTAMFO · engineer · Cameroon (UTC+1)