| Required Parameters | Possible Values | Description |
| client | Client ID | The numeric ID of the existing client that the invoice being added for |
| item_x | string | The item to be invoiced. Increment x to each new item to appear on the invoice. For example, to create an invoice with two items, the first item to appear on the invoice should be passed as item_1, the second as item_2, and so forth |
| qty_x | number | The quantity of the corresponding item_x item to be added |
| rate_x | decimal | The rate (charge) (without currency symbol - i.e. 10.00) of the corresponding item_x item to be added |
| tax_x | percentage | The tax rate to be charged against the corresponding item_x item to be added. If omitted, the global tax rate will be used |
| Optional Parameters | Possible Values | Description |
| type | regular | deposit | cancel | credit | The type of invoice to be created. A value of "deposit" denotes a Deposit Invoice, a value of "cancel" denotes a Cancellation Invoice, and a value of "credit" denotes a Credit Note. If omitted, a regular invoice will be created |
| notes | string | Additional notes to appear on the invoice |
| internal_notes | string | Additional internal notes associated with the invoice |
| term | number | The number of days allowed for the client to pay from the date of invoice. If omitted, the global Default Tax Amount setting will be used |
| paid | decimal | The amount paid against the invoice (without currency symbol - i.e. 10.00) |
| credit | decimal | The amount of credit applied to the invoice (without currency symbol - i.e. 10.00) |
| refunded | decimal | The amount refunded against the invoice (without currency symbol - i.e. 10.00) |
MIDAS API: add_invoice
MIDAS API: add_invoice