> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# What is core banking?

> A plain definition of core banking, what it manages (accounts, balances, transactions), and the five responsibilities we use to explain a modern core system.

A **core banking system** is the central platform a financial institution runs on. It manages **accounts, balances, transactions, the customers behind them, and money moving in and out**, all in one place, as a single source of truth.

Underneath all of it sits one idea that ties everything together: a trustworthy record of **who owns what** and **what moved**. The other jobs all connect to it by feeding it, moving value through it, reading it, and proving it's right. That's what makes banking *banking*: money can never be quietly lost or invented.

## Why it's harder than it looks

***

Keeping that record right is deceptively hard, and it's the reason most of the system exists:

* **It must always balance**: money can't appear or disappear, ever.
* **It has to stay correct at scale**: millions of movements, all consistent with each other.
* **It must be provable**: to auditors and regulators, long after the fact.

## How we'll explain it: five jobs

***

There are many ways to describe a core banking platform. In this guide we use **five core responsibilities**. This is how we organize the topic for learning, not an official taxonomy.

| Job               | What it does                                                                                                            |
| ----------------- | ----------------------------------------------------------------------------------------------------------------------- |
| **Record value**  | Keeps the trustworthy record of who owns what, balanced so nothing is lost or invented. Everything else builds on this. |
| **Move value**    | Brings money in, sends it out, and transfers it between accounts.                                                       |
| **Identify**      | Registers the people and companies behind the accounts.                                                                 |
| **Report**        | Turns the raw record into statements and reports you — and regulators — can read.                                       |
| **Trace & prove** | Keeps an auditable trail of everything that happened.                                                                   |

The **Ledger** is the foundation, but it's only **one of the five**. A complete core banking system is all five of them together, not a Ledger with extras bolted on. The other four build on the Ledger once it records value. Capabilities like **fees** attach to it to extend it.

You adopt these pieces one at a time, not as a single machine you switch on. The same handful of ideas (accounts, balances, movements) run through all of them. Learn those once, here, and the rest of the documentation gets much easier to follow.

## Next steps

***

<Note>
  **See it in Lerian**

  See how these jobs map to real solutions in the [Core banking vision](/en/start-here/about-lerian/core-banking-vision) and [Products and plugins](/en/products/products-and-plugins).
</Note>