Template Usage

When creating an invoice using a template (by specifying templateId), certain fields will be automatically populated from the template unless it is not explicitly overridden in the request:

• lineItems
• memo
• taxPercentage
• currency

Payment Preferences

The paymentMethodPreferences array allows you to specify:

• Which payment methods are accepted (paymentMethodTypes)
• If transaction fee would be paid by the client/company, or by your account

Line Items

When creating line items, you must provide:

For one-off items:

• amount (required) - Amount in cents
• description (optional) - Description of the item
• quantity (required) - Quantity of the item (supports decimals)

For recurring price items:

• priceId (required) - ID of the Prices object
• quantity (required) - Quantity of the item (supports decimals)

All line items must have either:

• amount + quantity for one-off items, OR
• priceId + quantityfor recurring price items

This makes it clearer that quantity is always required, and description is optional only for one-off line items.