Writing

Essays on African economies, mobile money, crypto rails and the craft of building financial software.

Mobile Money

The float is the product

I spent four years building on Kenya's mobile-money rails before I understood what I was actually building on: not a payments company, but something much closer to a narrow bank.

12 Sep 2026
11 min
Crypto

Stablecoins are a treasury tool before they are a payment rail

The importers I know moving dollars on-chain are not avoiding banks. They are avoiding the queue for them.

4 Sep 2026
6 min
Economies

Malawi's kwacha problem is a logistics problem

Devaluation takes the headlines. The binding constraint is how long a tonne of fertiliser sits at Beira.

28 Aug 2026
9 min
Building

Idempotency is a product decision, not an engineering one

Every retry policy encodes a belief about who absorbs the cost of uncertainty. Usually it's the customer.

19 Aug 2026
2 min
Mobile Money

A nicer front end on someone else's monetary policy

I asked everyone I met in Nairobi whether they used a crypto neobank. I could not find one person.

7 Aug 2026
3 min
Crypto

On-chain does not mean off-regulator

The compliance surface doesn't disappear when you change the rail. It moves to the edges, where nobody owns it.

31 Jul 2026
2 min
Economies

What the Nairobi–Kampala corridor tells you about integration

Two currencies, one trade route, and a settlement lag that quietly taxes everyone using it.

24 Jul 2026
4 min
Building

The ledger I wish I'd written first

Three rewrites later, here is the double-entry core I'd start every payments product with.

2 Jul 2026
3 min
Mthunzi
mthunzi.xyz
Colophon. Set in Fraunces and Source Serif 4, with Inter for labels. Charts drawn by hand in SVG. Written and built by Mthunzi Sabali.