> ## 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. # Midaz entities > See how Midaz core entities — Organizations, Ledgers, Assets, Portfolios, Accounts, Segments, and Balances — connect to power financial operations at scale. This diagram shows how the main building blocks of Midaz connect to support financial operations at scale. Figure 1 gives an overview of how the system works. Midaz core building blocks and how its interconnected domains fit together to support financial operations at scale ## Core components *** ### Midaz Midaz is at the center. It coordinates everything, from data persistence to business logic. ### Data Layer All data flows into the persistent **data layer**. This layer gives the system durability, consistency, and performance. ## Domains and relationships *** ### Organizations Each organization is a distinct environment in Midaz. It can hold one or many ledgers, based on how you structure your data. ### Ledgers A ledger holds all financial activity. It tracks balances, stores assets, and powers transactions. Every ledger belongs to an organization. From here, the system branches into: * **Assets**: define the kind of value you track. * **Portfolios**: group related accounts under a shared purpose. ### Assets Assets define the units of value, like BRL, USD, points, or tokens. Each account uses one specific asset. ### Portfolios Portfolios group accounts by business logic. You can create as many portfolios as you need to organize your financial structure. Each portfolio contains one or more accounts. ### Accounts & Segments An account belongs to a portfolio and represents an individual balance. **Segments** group accounts, so you can isolate data by customer, product, region, or any other dimension. Segments help you track and report with precision. **Account Types** classify accounts by nature and purpose. They enable transaction routing and operational validation across account categories. ### Balance A **Balance** represents the net amount an **Account** holds of a given **Asset** in a specific **Ledger**. * An account can carry **multiple balances**. Each has a `balanceKey` (e.g. `default`, `collateral`, `operational`) to partition funds without splitting the account. * An **external account** has only one balance (`default`). * If you omit `balanceKey` in a transaction, Midaz uses the default balance. * Midaz derives balances automatically from ledger operations. You can list, fetch, or (in admin or test scenarios) adjust them manually. * The Valkey cache key includes `balanceKey` in its format: `balance:{transactions}:::#`. ### Transactions A transaction moves value between accounts. Each transaction contains **operations** (debits and credits). This keeps your logic consistent, traceable, and aligned with your business model and accounting policies. ### Accounting Routes entities The [Accounting Routes entities](/en/midaz/transaction-routing-entities) extend Midaz. They create a structured system that guarantees correct annotations and correct financial-flow directions. It has two parts: * **Operation Routes:** define atomic transaction behaviors. Each route sets how Midaz annotates and directs one financial movement, based on your business rules and accounting standards. * **Accounting Routes:** orchestrate multiple Operation Routes into balanced financial events. They enforce double-entry validation and keep transaction integrity across all accounts. (The API calls this `transactionRoute`.) This pair forms a self-governing system. Midaz automatically validates each transaction for correct annotation and flow direction. ## In short *** Midaz gives you a modular structure: * Organizations manage ledgers. * Ledgers hold assets, portfolios, and accounting structures. * Portfolios contain accounts, grouped by segment. * Transactions move value and trigger accounting treatments. * Your data stays synced, traceable, and ready for financial reporting. **Need help designing your Midaz setup?** Our consulting service can help you tailor the structure to your organization's needs. This applies whether you start from scratch or optimize an existing setup. [Contact us](https://lerian.studio/contact) to learn more.