> ## Documentation Index > Fetch the complete documentation index at: https://ownpay.org/docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > OwnPay is licensed under AGPL-3.0 and is completely free - no licensing fees. > Production docs URL: https://ownpay.org/docs - append .md to any page URL for clean markdown. > OwnPay requires PHP 8.3+, MySQL/MariaDB, and Redis. > MCP server available at https://ownpay.org/docs/mcp for programmatic documentation queries. > Use root-relative links (e.g. /quickstart) for internal navigation - do NOT include /docs prefix. > Plugin development: consult /developer/plugins/ pages for correct interfaces and manifests. > Canonical locations: API auth = /api/authentication, webhook verification = /api/webhooks, rate limits = /resources/rate-limiting, transaction statuses = /fundamentals/payment-flow. > The documentation uses the Diataxis framework: Tutorials (learning), How-to (tasks), Reference (lookup), Explanation (understanding). # Ledger - Double-Entry Bookkeeping for Payments > OwnPay records every payment, fee, and transfer as balanced debit-credit pairs using double-entry bookkeeping with bcmath precision and brand isolation. This documentation is for OwnPay v0.2.0-beta, a open-source, self-hosted PHP 8.3 payment gateway with multi-brand support, 100+ payment gateways, and double-entry ledger. It is licensed under AGPL-3.0 with zero transaction fees. The docs URL is [https://ownpay.org/docs](https://ownpay.org/docs). API base URL is `https://your-domain.com/api/v1` with Bearer token authentication. Amounts are bcmath strings. The platform supports 4 plugin types: gateway, addon, theme, and integration. Canonical locations: API auth = /api/authentication, webhook verification = /api/webhooks, rate limits = /resources/rate-limiting, transaction statuses = /fundamentals/payment-flow. The documentation follows the Diataxis framework (Tutorial, How-to, Reference, Explanation). Every time money moves in OwnPay - a customer pays, a gateway deducts fees, a refund is issued - the system records it as a pair of balanced journal entries. This is **double-entry bookkeeping**, the same method used by accounting software and banks. It means you can always trace where money came from and where it went, and the total debits always equal the total credits. ## How double-entry works in OwnPay When a \$100 payment completes through Stripe (with a \$2.90 gateway fee), OwnPay creates four ledger entries across three accounts: |"payment completed"| C1 R1 -->|"payment completed"| G1 style C1 fill:#e8f5e9,stroke:#2e7d32 style G1 fill:#fce4ec,stroke:#c62828 style R1 fill:#e3f2fd,stroke:#1565c0 `} /> The net effect: **\$100.00 credit = \$97.10 debit + \$2.90 debit**. The books balance to zero. ## Account types OwnPay uses standard GAAP account categories: | Account type | Examples | Debit effect | Credit effect | | :------------ | :-------------------------------- | :---------------- | :---------------- | | **Asset** | Cash, Customer Receivable | Increases balance | Decreases balance | | **Expense** | Gateway Fee Revenue, Platform Fee | Increases balance | Decreases balance | | **Liability** | Refund Payable | Decreases balance | Increases balance | | **Equity** | Retained Earnings | Decreases balance | Increases balance | ## Balance calculation All monetary math uses PHP's `bcmath` extension - never floating-point arithmetic. Balances are validated at **4-decimal precision** using `bccomp()`. ```php theme={"theme":{"light":"github-light","dark":"github-dark"}} // Internal balance validation (simplified) $debits = bcadd($entry1->debit, $entry2->debit, 4); // "100.0000" $credits = bcadd($entry1->credit, $entry2->credit, 4); // "100.0000" if (bccomp($debits, $credits, 4) !== 0) { throw new InvalidArgumentException('Journal entries must balance'); } ``` Never manually update the `op_ledger_accounts.balance` column. Always use `LedgerService` - direct SQL edits will cause reconciliation mismatches. ## Double-post prevention OwnPay guards against recording the same payment twice. Before inserting ledger entries, the system acquires a row lock: ```sql theme={"theme":{"light":"github-light","dark":"github-dark"}} SELECT * FROM op_ledger_transactions WHERE merchant_id = ? AND reference_type = ? AND reference_id = ? FOR UPDATE ``` If a matching row exists, the operation is skipped. This runs inside a database transaction, so concurrent requests are serialized safely. ## Brand isolation Ledger accounts are scoped to a `merchant_id` (brand). Brand A's cash balance is completely independent of Brand B's. The repository enforces this at the query level: ```php theme={"theme":{"light":"github-light","dark":"github-dark"}} $account = $ledgerRepo->findOrCreateAccount($name, $type, $currency, $merchantId); ``` ## Reconciliation You can verify your ledger balances against gateway settlements at any time. OwnPay includes a CLI reconciliation command: ```bash theme={"theme":{"light":"github-light","dark":"github-dark"}} php public/index.php admin/reconcile --merchant=YOUR_MERCHANT_ID ``` This compares OwnPay's recorded transactions against the gateway's reported totals and flags any discrepancies. For the GUI-based version, see the [Balance Verification](/docs/reports/balance-verification) page in the admin dashboard. ## Related pages * [Payments - Ledger](/docs/payments/ledger) - view ledger entries and journal details in the UI * [Balance verification](/docs/reports/balance-verification) - run reconciliation audits from the dashboard * [Brands](/docs/fundamentals/brands) - understand brand-level ledger isolation * [Transaction statuses](/docs/fundamentals/payment-flow) - which states trigger ledger entries * [Common errors](/docs/resources/common-errors) - troubleshooting reconciliation mismatches ## Related topics - [Features and Capabilities](/docs/resources/features.md) - [OwnPay Architecture: PHP Core, Middleware, and Plugins](/docs/resources/architecture.md) - [OwnPay Skills for AI Agents - Platform Knowledge Pack](/docs/developer/ai/skills.md) - [Ledger UI](/docs/payments/ledger.md) - [Glossary](/docs/resources/glossary.md)