SIMBA, 60 days, and then the hard part

I gave myself a hundred days. It took sixty.

That was Angela Yu's 100 Days of Code on Udemy, a day of Python every day until it was done. I did not skip the dull days, which are most of them, and I did not let myself move on until each one actually ran. Nothing about it was glamorous. It is simply the reason I can now look at a piece of code and tell whether it is right, and that turns out to be the only qualification that matters.

Because I do not write most of it any more. I direct an AI agent that writes, tests and fixes, while I check the direction and the quality. I am the manager; it is the team. The sixty days, plus a good computer, are what let me be a manager rather than a hostage. When it is confidently wrong, and it is sometimes confidently wrong, I can see it.

Then I pointed all of it at one problem.

SIMBA is our savings and credit co-operative, sixteen members, real money. For its first year it lived in a single Excel file. For its first year it lived in a single Excel file. That file was not a toy: every share, every loan, every repayment, twenty-eight loans and USD27,000 advanced, no arrears. But a spreadsheet cannot say no. It will let you record an approval the Board never gave, and pay out money you do not hold.

In August I replaced it. One HTML file first, then a real database behind it, a domain, and sixteen people signing in with their own passwords to look at their own money. It has been live every day since.

What it has become is the part I did not expect.

Robust. Every rule in our Regulations is now something the database refuses to break, not something we remember. Code is the law. No officer can move money alone. Nobody countersigns their own payment. The system will not create a member without a two-thirds vote of the Board behind them. There are 1,824 automated tests, and all of them run before a single line reaches a member.

Auditable. The books reconcile to the cent. Every screen cites the regulation it enforces. The Register of Members is written by the same function that causes the event, so it cannot fall behind what it records. When we audited the system against our own Constitution, it found five faults that would have moved money wrongly, and we wrote down the ones we got wrong as well as the ones we fixed. An auditor can be shown the rule and the code that enforces it, side by side.

That combination is what turns sixteen friends with a WhatsApp group into something more interesting. Most small savings clubs die of their own bookkeeping. Ours has a record a Registrar can trust and a structure that will carry twenty-five members as easily as sixteen. On our own projections the problem in three years is not raising capital. It is finding enough good places among ourselves to put it.

Sixty days of Python bought that. It remains the best trade I have made.

SIMBA is at simba-sacco.com