Update an invoice | Mitu API Documentation

curl -X PATCH https://api.mitu.ai/v1/invoices/id \
     -H "x-api-key: <apiKey>" \
     -H "Content-Type: application/json" \
     -d '{
  "description": "September retainer (revised)",
  "lineItems": [
    {
      "name": "Integration support",
      "quantity": 12,
      "amount": 150
    }
  ],
  "dueAt": "2026-10-07T23:59:59.000Z"
}'

{
  "message": "Invoice retrieved successfully",
  "data": {
    "id": "inv_4k2m9x7ptw3c",
    "invoice_number": "INV-2026-0041",
    "status": "draft",
    "recipient": {
      "id": "rcp_ds9hazr8jd3l",
      "name": "Ada Lovelace",
      "email": "ada@example.com",
      "phone": null,
      "created_at": "2026-09-09T10:12:04.512Z"
    },
    "description": "September retainer",
    "line_items": [
      {
        "name": "Integration support",
        "quantity": 10,
        "amount": 150,
        "description": "10 hours"
      }
    ],
    "subtotal": "1500.00",
    "tax_amount": "0.00",
    "discount_amount": "0.00",
    "amount": "1500.00",
    "currency": "USD",
    "url": {
      "checkout": "https://mitu.ai/invoice/inv_4k2m9x7ptw3c",
      "agent": "https://api.mitu.ai/invoice/inv_4k2m9x7ptw3c"
    },
    "due_at": "2026-09-30T23:59:59.000Z",
    "sent_at": null,
    "viewed_at": null,
    "paid_at": null,
    "created_at": "2026-09-09T10:12:04.881Z"
  }
}

Update an invoice.

Authentication

x-api-keystring

Account API key used to authenticate server-side requests. Use the credentials issued for the same environment as the API base URL.

Path parameters

idstringRequired

Unique identifier of the resource.

Request

This endpoint expects an object.

recipientIdstringOptional

Bill a different saved recipient.

descriptionstringOptional<=2000 characters

lineItemslist of objectsOptional

taxAmountdoubleOptional>=0

discountAmountdoubleOptional>=0

dueAtdatetimeOptional

Response

Invoice updated successfully.

messagestring

dataobject

Response fields are snake_case; request fields are camelCase.

Errors

400

Bad Request Error

401

Unauthorized Error

403

Forbidden Error

404

Not Found Error

409

Conflict Error

422

Unprocessable Entity Error

429

Too Many Requests Error

500

Internal Server Error