Core Concepts

The fundamental building blocks of Bkper — Accounts, Transactions, Groups, Books, Collections, and Events — and how they work together to track financial activity.

Bkper tracks resources — money, inventory, or anything countable — as movements between places. Every financial event is recorded as an amount moving from one Account to another. This from-to model replaces the traditional language of debits and credits with something intuitive: resources leave one place and arrive at another.

A transaction in Bkper showing an amount moving from one account to another

The system enforces a zero-sum invariant — the total of all records always equals zero. Nothing is created or destroyed, only transferred. This makes Bkper a double-entry bookkeeping system where every transaction automatically produces balanced entries.

For those familiar with traditional accounting, “from” corresponds to credit and “to” corresponds to debit — but the explicit flow eliminates the need to memorize these rules. Learn more about double-entry bookkeeping.

Accounts

Accounts are the places where resources reside or flow through. An Account can represent a bank, a category, a customer, a project, or anything else that holds or transfers value. You define what each Account represents and structure them at whatever level of detail suits your needs.

An Account registers all incoming and outgoing amounts through transactions. The sum of these movements produces the account’s balance — the net result of everything that has flowed in and out.

Account Types

Bkper organizes Accounts into four types that determine how an Account behaves and where it appears in your financial structure:

Asset (blue) — permanent. Real resources you own: bank accounts, cash, receivables. Balances carry forward continuously, showing your position at any point in time.
Liability (yellow) — permanent. Obligations you owe: credit cards, loans, supplier debts. Balances also carry forward continuously.
Incoming (green) — non-permanent. Revenue sources: salary, sales, interest. Balances track activity within a period and reset to zero for the next one.
Outgoing (red) — non-permanent. Expenses and costs: rent, supplies, payroll. Balances also track activity within a period.

The four account types in Bkper: Asset (blue), Liability (yellow), Incoming (green), and Outgoing (red)

Learn more about how account types shape your financial structure.

Transactions

A Transaction is the atomic unit of financial activity. It captures:

Date — when it happened
Amount — how much moved
From Account — where the resource came from
To Account — where it went
Description — what happened

The from-to model makes every event explicit and traceable.

Transactions in Bkper showing amounts moving between accounts with dates, descriptions, and balances

A transaction is nothing more than moving a resource from one place to another. When you pay a taxi for a ride, the amount that goes from your wallet to the driver represents a transaction.

If any essential element is missing, the transaction is saved as an incomplete draft.

Transaction States

Transactions move through a lifecycle with four states:

Draft — incomplete or unposted. Does not affect balances.
Unchecked — posted and updates balances, but remains editable.
Checked — reviewed and locked for integrity.
Trashed — removed from balances, but recoverable.

Transaction state diagram showing the flow between Draft, Unchecked, Checked, and Trashed states

This structure puts a human in the loop — you review and confirm before records become permanent. Learn more about how transaction states work.

Groups

Groups organize Accounts into hierarchies for reporting and analysis. They don’t change the underlying data — they provide structure for understanding it. Groups consolidate account balances, so you can see totals for categories like “Expenses” or “Assets” at a glance.

Groups support hierarchies (groups of groups) and multiple perspectives — an Account can belong to different groups in different hierarchies.

Groups inherit the nature of the accounts they contain:

Asset-only group — behaves as Asset (blue)
Liability-only group — behaves as Liability (yellow)
Mixed Asset + Liability — shows Equity (gray, net balance)
Incoming-only group — behaves as Income (green)
Outgoing-only group — behaves as Expense (red)
Mixed Incoming + Outgoing — shows Net Result (gray)

Hierarchical groups in Bkper showing groups within groups for structured reporting

Books

A Book is a self-contained ledger — the complete scope of an entity, whether an individual, a project, or a business. Every Account, Transaction, and Group lives within a Book, and every Book balances to zero. Books can track any countable resource using the same from-to model.

A Bkper Book containing Accounts, Groups, and Transactions organized by type

The sum of all credits and debits recorded in a Book always tallies to zero — nothing is created or destroyed, only transferred. For more complex entities, multiple Books can be organized into a Collection.

Balances

Balances are always calculated from Transactions, never stored independently. The total balance across all Accounts in a Book is always zero. Account type determines how balances behave over time:

Permanent Accounts (Asset & Liability) — balance to a date, showing cumulative position at a point in time.
Non-permanent Accounts (Incoming & Outgoing) — balance within a period, showing activity during a timeframe.

Bkper maintains a continuous ledger with no concept of closing periods — the same ledger serves all time-based queries automatically. Learn more about reporting periods and balance auditing.

Custom Properties

Custom Properties are key-value pairs attachable to any entity — Books, Accounts, Groups, Transactions, Collections, and Files. They add context, metadata, and meaning beyond core financial data.

By attaching properties like invoice: inv123456 or exc_code: BRL, entities become rich with information that can drive automation and reporting — without changing the core model. Learn more about Custom Properties.

Hashtags

Hashtags are lightweight labels on Transactions that enable multi-dimensional tracking. They complement the Account structure by adding dynamic categorization — a single transaction might carry #team_marketing #project_alpha #q1_campaign, enabling filtering and analysis from any perspective.

Unlike Account structures, Hashtags can be added or removed as needs evolve, making them ideal for cost allocation, project tracking, and ad-hoc analysis. Learn more about Hashtags.

Collections

Collections group related Books for organization and consolidated views. Each Book remains self-contained and balanced — Collections simply provide navigation and structure across multiple Books. You might track resources in multiple currencies, or organize branch offices in one collection.

Collections can also serve as references for automations (Bots or Apps) that work on all Books in the collection. Learn more about Working with Collections.

Events

Every action in a Book — posting a transaction, editing an account, adding a comment — generates an Event. Events record who (a user) or what (a bot, an automation) performed the action and when, forming a complete audit trail essential for collaboration and trust.

Events are also the foundation of Bkper’s automation model. Bots and Agents listen for specific event types and react automatically — for example, calculating taxes when a transaction is posted or converting currencies when one is checked.

Next Steps

Ready to put these concepts into practice? Start here: