Intro to Accounting for Software People

Most engineers in fintech treat accounting as a business concern — someone else's problem, handed off to the Finance team. This is a mistake. Accounting is a constraint system. Its core invariant — sum(all_postings) = 0, always — is a conservation law, and violating it produces the same class of bugs as violating referential integrity or overflowing a counter.

This curriculum teaches accounting from first principles, the way you'd want a systems concept taught: with invariants, failure modes, and production consequences. It covers double-entry bookkeeping, account types, two-phase settlement, multi-currency inventory, P&L accounting, and the fintech-specific patterns that production ledgers require.

Every concept is shown in two representations simultaneously — Beancount (text-based, human-readable, a reasoning tool) and TigerBeetle (binary, OLTP-grade, a production tool). The same invariants hold at both levels. Seeing them side by side makes the abstractions collapse in the right way.

How to use this

Work linearly. Each module has:

• A concept section — the core invariant or pattern
• A Socratic dialogue — try to answer before expanding
• Adversarial exercises — where the actual learning happens. Do not skip them.