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Walk into a library and the structure is obvious before anyone explains it. There’s the library itself, the catalog that organizes everything, the shelves, what’s actually sitting on each shelf right now, and the kind of thing a shelf holds. A core banking system is built from five pieces that line up the same way. You don’t need to memorize them. You just need to see how each one rests on the one before it.

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They stack in order

Each block depends on the one above it: a shelf sits in a library, a balance sits in an account. Here they are, top to bottom.
  • Organization — your company, the outer boundary of everything you run. The library building itself. All your records live inside it and belong to it.
  • Ledger — one self-contained book of records. The catalog. You can keep more than one — say, one per business line or per region — and each is its own balanced, independent set of books.
  • Asset — the kind of value being tracked: a currency like USD, loyalty points, anything countable. The category of thing on a shelf. Tracking the unit separately from the amount is what lets the system know that 100 of one thing isn’t 100 of another.
  • Account — a container that holds value of one asset and can send and receive it. A single shelf. Every movement of money has accounts on both sides.
  • Balance — the amount an account holds right now. What’s actually on the shelf at this moment.
An Organization can hold many Ledgers; a Ledger holds many Accounts; an Account is always tied to one Asset and carries a Balance of it. Read top to bottom, each block is the home of the next.

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A balance is a result, not a setting

Here’s the one idea worth slowing down on. A balance is not a number you type in and adjust by hand. It’s the result of every movement into and out of the account, added up. Money arrives, money leaves, and the balance is simply where that leaves you. That’s why the books stay trustworthy: a balance can’t be quietly edited, only moved into the shape it has by recorded movements with two sides each.
A balance isn’t always one single number you can spend. Part of it can be available — yours to use now — while part is held, set aside for a movement that hasn’t finished. We’ll unpack available versus held when we look at how money moves.

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In short

  • The five building blocks stack in order: Organization → Ledger → Account → Balance, with an Asset defining what an account holds.
  • An Organization is your company; a Ledger is one self-contained book; an Account holds and moves value; a Balance is what’s in it now.
  • An Asset is the kind of value — tracked separately so amounts of different things never get confused.
  • A balance is a result of recorded movements, never a number you set by hand — and it can be split into available and held.
These five nouns are the vocabulary for everything else. Once they feel natural, movements, holders, and fees are just things you do with them.
See it in LerianSee the building blocks in practice: Core entities, Ledgers, Accounts, Balances, and Assets.