August 19, 2026

Create an Expense

POST /v3/Expenses creates an expense and associates it with a work item, contact or organization.

POST /v3/Expenses

{
  "Timeline": {
    "EntityType": "WorkItem",
    "EntityKey": "2m6pSFxRzcF2"
  },
  "ExpenseDate": "2026-08-14T00:00:00Z",
  "Value": 240.5,
  "BillableValue": 240.5,
  "Description": "Courier fees for year-end documents"
}

Timeline is the entity the expense belongs to, and follows the same shape as the timeline links on notes. EntityType must be one of:

ExpenseDate, Value, BillableValue and Description are all required. Value is the cost of the expense and BillableValue the portion you intend to bill your client — set BillableValue to 0 for an expense you’re absorbing, or to the same amount as Value to pass it on in full. Neither can be negative, and Description is limited to 250 characters.

A successful request returns 201 Created with the new ExpenseKey:

{
  "ExpenseKey": "3nB7kQvXLmT",
  "Timeline": {
    "EntityType": "WorkItem",
    "EntityKey": "2m6pSFxRzcF2"
  },
  "ExpenseDate": "2026-08-14T00:00:00Z",
  "Value": 240.5,
  "BillableValue": 240.5,
  "Description": "Courier fees for year-end documents"
}

Once created, a billable expense is picked up by invoicing the same way an expense entered in Karbon is, and appears in the Expenses section of GET /v3/Invoices/{InvoiceKey}?$expand=Data.

Expenses cannot yet be listed, updated or deleted through the API, and expense types aren’t supported on create.