🛁 🛁 🛁 The Ultimate Bookkeeping System (TUBS) 🛁 🛁 🛁

Multi-homed data

Your bookkeeping data already lives in many places: your bank, your invoicing tool, your time tracker, your accountant's package. TUBS does not ask you to move it all into one new system. Instead, a record can live in several systems at once, and the copies are kept in step. Three building blocks do this:

• syncables reads each platform's API, driven by its OpenAPI description.
• Devonian translates each platform's records to a shared model and back, using lenses.
• Reflector is the sync engine that keeps the copies in step.

Computed cells

Like a spreadsheet, some values are formulas over other values: an invoice total, an account balance, the VAT for a quarter. The design principle is store the formula, not the value. When copies from different systems are merged, a stored total can silently go stale; a formula is recomputed from the merged data.

The same idea covers the rules of bookkeeping. An invariant, such as "the balance equals the sum of the transactions", is a computed cell that must be true. If a merge breaks one, it shows up as something to review and fix, instead of as silent corruption.

Commit messages

Like a Git repository, TUBS keeps not only the current state but also its history, with a message for every change saying why it was made: "marked invoice 2026-041 as paid, matched to bank line 3812". Changes proposed by people, by apps and by AI agents are recorded the same way. They can be reviewed before they are applied, and traced back afterwards.