Marks an existing invoice as paid using an offline payment method, such as cash, check, or gift card. This endpoint is useful for reconciling invoices when payments are made outside of the Stax system.

Key Features

Marks an invoice as paid with a manual payment method (e.g., cash, check).
Updates the invoice's paid_at timestamp to reflect the payment time.
Adjusts the invoice's status to PAID or PARTIALLY APPLIED depending on the payment amount.
Supports partial payments, allowing flexibility for invoices that are not fully paid at once.

Usage Notes

Payment Methods

This endpoint is designed for offline payments. Supported payment methods include:

Cash
Check
Gift Card

Partial Payments

When marking an invoice as partially paid:

The invoice's status will be updated to PARTIALLY APPLIED.
Additional payments can be recorded until the invoice is fully paid.

Timestamp Updates

The paid_at field is automatically set to the current time to reflect when the manual payment was received.

Response Structure

Code	Response	Reason
200	Success	The invoice was successfully marked as paid.
400	Bad Request	Invalid invoice ID or payment details.
401	Unauthorized	Authentication failed.
404	Not Found	An invoice with the specified ID does not exist.
500	Internal Server Error	Unexpected server error.

Important Considerations

Invoice Eligibility: The invoice must exist and must not already be marked as fully paid.
Partial Payments: Use this endpoint for incremental payments. Once the total is paid, the status will automatically update to PAID.
Audit Trail: Each payment is logged for tracking and reporting purposes.
Customer Visibility: Marking an invoice as paid in cash or check will not generate a payment receipt. You must issue one manually if required.