> ## Documentation Index > Fetch the complete documentation index at: https://docs.wave.sa/llms.txt > Use this file to discover all available pages before exploring further. # Billing > How the wallet, top-up, project budgets and invoices work in the Wave portal. Wave has one **wallet** for each organization. Charges come out of the wallet. You manage the wallet on the **Billing** page of the portal. All amounts are in Saudi riyals (SAR). ## Who can do what | Role | What the role can do on the Billing page | | - | - | | `owner` | Everything: read, top up, split the wallet across projects, turn project budgets on or off, generate an invoice. | | `billing` | Read, top up, and split the wallet across projects. | | `admin` | Read, and generate an invoice. An `admin` cannot top up or split the wallet. | | `developer`, `supervisor`, `agent` | No access to the Billing page. | The Billing page is open from the first day. You do not need a Go-Live to use it. ## Wallet The top of the Billing page shows your **balance**. Below it you see these parts: * **Rate plan.** The unit price of each usage type. * **Usage.** The charges of the last 30 days, with the price in SAR. The list shows at most 500 charges. * **Invoices.** The invoices of your organization. When the balance is 0 or less, an action that costs money returns `402 INSUFFICIENT_CREDITS`. For example, buying a number is such an action. Top up to continue. ### Call charges A call charge counts each started minute of an answered production call. The minimum is one minute. A sandbox call is not billed. See [Sandbox mode](https://docs.wave.sa/sandbox-mode.md). Each charge shows on the **Usage** list, and the amount comes out of the wallet. ## Top up 1. Open **Billing**. 2. Select an amount (50, 100 or 500 SAR), or type your own amount. The amount must be more than 0 and not more than 100,000 SAR. 3. Select **Top up**. 4. The portal sends you to the payment page of the payment provider. Pay there with a card or Apple Pay. After you pay, the portal shows **Payment received** and the new balance. The payment provider tells Wave that the payment is complete, and then Wave adds the money to the wallet. If the page shows **Payment not confirmed yet**, wait a moment and select **Check again**. Wave adds the money once only, also if you select **Check again** many times. Only the `owner` and the `billing` role can top up. If the payment provider cannot start the payment, the portal shows an error (`502 PAYMENT_FAILED`). Try again later. ## Project budgets By default, all projects spend from the main balance. With **project budgets**, you give each project its own part of the wallet. A project can spend only from its own budget. **Project budgets** is a switch for the whole organization. Only the `owner` can turn it on or off. * **Off (default).** Each charge comes out of the main balance. * **On.** Each project spends from its own budget. When the budget of a project reaches 0, the project stops with `402 INSUFFICIENT_PROJECT_BALANCE`. > [!WARNING] > > When you turn the switch on, no money moves. A project that has no budget stops > working until you add money to it. To move money: 1. In **Project budgets**, find the project. The **Unallocated** amount is the part of the wallet that no project has. 2. Type an amount in SAR (at most 2 decimal places). 3. Select **Add to project** to move the money from the unallocated amount to the project. Select **Take back** to move money from the project to the unallocated amount. If the unallocated amount is less than the amount that you ask for, Wave returns `402 INSUFFICIENT_POOL_BALANCE`. If the project has less than the amount that you take back, Wave returns `402 INSUFFICIENT_PROJECT_BALANCE`. Select **Ledger** on a project to see all its entries: money added, money taken back, usage, refunds and adjustments. Each entry shows the balance after it. ## Invoices An invoice groups the usage charges of one period that no invoice has yet. It shows three amounts: | Amount | Meaning | | - | - | | Net | The sum of the charges. | | VAT | 15% of the net amount. | | Gross | The net amount plus VAT. | The **Invoices** list shows the period and the three amounts of each invoice. An invoice detail shows one line for each usage type, with the quantity and the net amount. An `owner` or an `admin` can select **Generate invoice**. This groups the charges of the current month so far that no invoice has yet. If there are no such charges, Wave makes no invoice. A charge is on one invoice only. ## Billing API The portal uses these routes. They need a portal session, not an API key. | Route | What it does | | - | - | | `GET /v1/billing/balance` | The balance of the wallet. | | `GET /v1/billing/usage` | The usage charges, with `from` and `to` (default: the last 30 days). | | `GET /v1/billing/invoices` | The list of invoices. | | `GET /v1/billing/invoices/{id}` | One invoice, with its line items. | | `POST /v1/billing/topup` | Start a top-up (`amount_sar`). | | `GET /v1/billing/projects` | The unallocated amount and the balance of each project. | | `POST /v1/billing/projects/{projectId}/allocate` and `/deallocate` | Move money to or from a project (`amount_sar`). | ## Errors | Status | Code | When | | - | - | - | | `402` | `INSUFFICIENT_CREDITS` | The balance is 0 or less. Top up. | | `402` | `INSUFFICIENT_PROJECT_BALANCE` | Project budgets are on and the budget of the project is used up. | | `402` | `INSUFFICIENT_POOL_BALANCE` | The unallocated amount is less than the amount that you ask for. | | `404` | `INVOICE_NOT_FOUND` | No such invoice in your organization. | | `502` | `PAYMENT_FAILED` | The payment provider could not start the top-up. | ## Next steps > [card] [Sandbox mode](https://docs.wave.sa/sandbox-mode.md) > > What sandbox keys can do, and what is not billed. > [card] [Errors](https://docs.wave.sa/errors.md) > > All error codes of the Wave API. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.