Meridian Ledger

A spreadsheet that finally broke.

Meridian ran their whole freelance accounting practice on one heroic spreadsheet — 14 tabs, a dozen named ranges, and a macro nobody dared touch. It worked until it didn't: one wrong paste and a quarter's reconciliation was gone.

The brief was narrow on purpose: keep the mental model of the spreadsheet, lose the fragility. No "platform," no roadmap fantasy. One job — double-entry that can't silently corrupt itself — done in a month.

One ledger, two sides, no surprises.

I modelled the core as an append-only journal: every entry is two balanced postings, nothing is ever edited in place, corrections are new entries. The UI hides the theory — it still looks like rows you type into — but the data underneath can be audited line by line.

Payments and bank imports came in week three; week four was reconciliation and the dull, important work of making errors impossible rather than merely unlikely.

The unglamorous parts.

Most of the value lived in the parts nobody demos: idempotent imports, a reconciliation diff that highlights only what changed, and exports that an accountant opens without complaint.