> For the complete documentation index, see [llms.txt](https://invoice4u.gitbook.io/invoice4u-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://invoice4u.gitbook.io/invoice4u-docs/documents/create-document-with-validation.md).

# Create a Document with Identifier Validation

Same as [Create a Document](/invoice4u-docs/documents/create-document.md), but with strict idempotency: if a document with the same `ApiIdentifier` (and type) already exists in your organization, the call **does not create a new document** — it returns the existing one with the `DocumentAlreadyCreated` error attached.

Use this endpoint when your system may retry requests (queues, webhooks, network timeouts).

## Endpoint

|              |                                                                        |
| ------------ | ---------------------------------------------------------------------- |
| **Method**   | `POST`                                                                 |
| **Path**     | `/CreateDocumentWithIdentifierValidation`                              |
| **Response** | `Document` — new one, or existing one + `DocumentAlreadyCreated` (134) |

## Request schema

Identical to [Create a Document](/invoice4u-docs/documents/create-document.md):

| Field   | Type     | Required | Description                                                                                               |
| ------- | -------- | -------- | --------------------------------------------------------------------------------------------------------- |
| `doc`   | Document | Yes      | The document. **Always set `ApiIdentifier`** — the deduplication key, unique per document in your system. |
| `token` | string   | Yes      | Authentication token.                                                                                     |

## Example request

```http
POST /Services/ApiService.svc/CreateDocumentWithIdentifierValidation HTTP/1.1
Host: apiqa.invoice4u.co.il
Content-Type: application/json

{
  "doc": {
    "DocumentType": 1,
    "Subject": "Order #10045",
    "ClientID": 88231,
    "ApiIdentifier": "order-10045-invoice",
    "Items": [
      { "Name": "Widget", "Quantity": 2, "Price": 50.0 }
    ],
    "AssociatedEmails": [
      { "Mail": "billing@acme.example" }
    ]
  },
  "token": "<token>"
}
```

## Duplicate response

When `ApiIdentifier` already exists, the response is the **existing** document plus the error:

```json
{
  "CreateDocumentWithIdentifierValidationResult": {
    "ID": "7f6a2c1e-8b4d-4f2a-9c3e-0d1e2f3a4b5c",
    "DocumentNumber": 20260119,
    "ApiIdentifier": "order-10045-invoice",
    "Errors": [
      { "ID": 134, "Error": "DocumentAlreadyCreated" }
    ]
  }
}
```

Treat error `134` with a returned `DocumentNumber > 0` as success-idempotent: the document already exists, no action needed.

## Retry flow

```mermaid
flowchart TD
    classDef step fill:#E7D9FC,stroke:#9B6DD6,color:#333
    classDef dec fill:#D2F0D2,stroke:#4CAF50,color:#333
    classDef err fill:#FFD9A0,stroke:#E8A33D,color:#333
    classDef cb fill:#BBDEFB,stroke:#42A5F5,color:#333

    A[Send with your<br/>ApiIdentifier]:::step --> B{Response?}:::dec
    B -- "Errors empty" --> G[Created ✓]:::cb
    B -- "DocumentAlreadyCreated 134<br/>+ DocumentNumber > 0" --> E[Already exists —<br/>use it, don't retry]:::cb
    B -- "timeout / TimeoutDB 147" --> C[GetDocumentByApiIdentifier]:::step
    C --> D{Document exists?}:::dec
    D -- ✓ --> E
    D -- ✗ --> F[Retry CreateDocumentWithIdentifierValidation<br/>SAME ApiIdentifier]:::step
    F --> B
    B -- "other error" --> H[Fix request →<br/>retry same identifier]:::err
    H --> F
```

## Errors

All [Create a Document errors](/invoice4u-docs/documents/create-document.md#common-errors) apply, plus the duplicate behavior above.

## Try it

## Create a document with idempotency by ApiIdentifier

> Same as CreateDocument, but if a document with the same ApiIdentifier and type already exists, the existing document is returned with error DocumentAlreadyCreated (134) instead of creating a duplicate.

```json
{"openapi":"3.0.3","info":{"title":"Invoice4U API","version":"1.0.0"},"tags":[{"name":"Documents","description":"Create and retrieve documents (invoices, receipts, etc.)."}],"servers":[{"url":"https://api.invoice4u.co.il/Services/ApiService.svc","description":"Production"},{"url":"https://apiqa.invoice4u.co.il/Services/ApiService.svc","description":"QA (staging)"}],"paths":{"/CreateDocumentWithIdentifierValidation":{"post":{"tags":["Documents"],"operationId":"CreateDocumentWithIdentifierValidation","summary":"Create a document with idempotency by ApiIdentifier","description":"Same as CreateDocument, but if a document with the same ApiIdentifier and type already exists, the existing document is returned with error DocumentAlreadyCreated (134) instead of creating a duplicate.","requestBody":{"required":true,"content":{"application/json":{"schema":{"type":"object","required":["doc","token"],"properties":{"doc":{"$ref":"#/components/schemas/Document"},"token":{"type":"string"}}}}}},"responses":{"200":{"description":"New or existing document.","content":{"application/json":{"schema":{"type":"object","properties":{"CreateDocumentWithIdentifierValidationResult":{"$ref":"#/components/schemas/Document"}}}}}}}}}},"components":{"schemas":{"Document":{"allOf":[{"$ref":"#/components/schemas/CommonObject"},{"type":"object","required":["DocumentType"],"properties":{"ID":{"type":"string","format":"uuid","readOnly":true},"DocumentNumber":{"type":"integer","format":"int64","readOnly":true,"description":"Legal sequential number, per type."},"DocumentType":{"type":"integer","description":"1 Invoice, 2 Receipt, 3 InvoiceReceipt, 4 InvoiceCredit, 5 ProformaInvoice, 6 InvoiceOrder, 7 InvoiceQuote, 8 InvoiceShip, 9 Deposits, 10 SupplierInvoiceToInventory, 13 PurchaseOrder.","enum":[1,2,3,4,5,6,7,8,9,10,13]},"Subject":{"type":"string","nullable":true},"ClientID":{"type":"integer","nullable":true,"description":"Existing customer ID. Required unless GeneralCustomer is supplied or the type doesn't need a customer."},"GeneralCustomer":{"$ref":"#/components/schemas/GenerelCustomer"},"Items":{"type":"array","nullable":true,"items":{"$ref":"#/components/schemas/DocumentItem"}},"Payments":{"type":"array","nullable":true,"items":{"$ref":"#/components/schemas/Payment"}},"Invoices":{"type":"array","nullable":true,"description":"Referenced documents (each with ID and ReceiptAmount). Requires DocumentReffType.","items":{"type":"object","properties":{"ID":{"type":"string","format":"uuid"},"ReceiptAmount":{"type":"number","format":"double"}}}},"DocumentReffType":{"type":"integer","description":"Type of the referenced documents."},"IssueDate":{"type":"string","format":"date-time","nullable":true,"description":"Defaults to today. Not in the future; not before your latest document of the type."},"Currency":{"type":"string","nullable":true},"ConversionRate":{"type":"number","format":"double","description":"Auto-resolved when 0."},"TaxPercentage":{"type":"number","format":"double","nullable":true},"TaxIncluded":{"type":"boolean","description":"Whether item prices include VAT."},"Discount":{"$ref":"#/components/schemas/Discount"},"BranchID":{"type":"integer","nullable":true,"description":"Defaults to the organization's default branch."},"Language":{"type":"integer","description":"1 Hebrew, 2 English."},"AssociatedEmails":{"type":"array","nullable":true,"items":{"$ref":"#/components/schemas/AssociatedEmail"}},"ExternalComments":{"type":"string","nullable":true,"maxLength":5000},"InternalComments":{"type":"string","nullable":true},"EmailCustomComment":{"type":"string","nullable":true},"ApiIdentifier":{"type":"string","nullable":true,"description":"Idempotency key. Auto-generated if missing."},"ApiDuplicityTimeValidation":{"type":"integer","description":"Duplicate-detection window in seconds. Default 60."},"PaymentDueDate":{"type":"string","format":"date-time","nullable":true},"Deduction":{"type":"number","format":"double","description":"Withholding-tax deduction (receipts)."},"CloseReceipt":{"type":"boolean"},"IsSelfInvoice":{"type":"boolean"},"SupplierId":{"type":"integer","nullable":true},"SupplierName":{"type":"string","nullable":true},"UseDecimalValues":{"type":"boolean"},"AutoFixPaymentsMismatchItems":{"type":"boolean","description":"Auto-fix ±0.01 rounding gaps between payments and items."},"AutoFixMismatchItemName":{"type":"string","nullable":true},"Total":{"type":"number","format":"double","readOnly":true},"TotalWithoutTax":{"type":"number","format":"double","readOnly":true},"TotalTaxAmount":{"type":"number","format":"double","readOnly":true},"StatusID":{"type":"integer","readOnly":true,"description":"1 Open, 2 Closed, 3 FullyCredited, 4 PartiallyCredited, 5 Cancelled."},"PrintOriginalPDFLink":{"type":"string","readOnly":true},"PrintCertifiedCopyPDFLink":{"type":"string","readOnly":true},"CipherText":{"type":"string","readOnly":true},"CipherTextOriginal":{"type":"string","readOnly":true},"AllocationNumber":{"type":"string","nullable":true,"readOnly":true},"Paid":{"type":"number","format":"double","readOnly":true},"CreditAmount":{"type":"number","format":"double","readOnly":true},"Balance":{"type":"number","format":"double","readOnly":true}}}]},"CommonObject":{"type":"object","description":"Response envelope inherited by most objects. Server-generated — never send these fields in requests. Always check Errors before using the payload.","properties":{"Errors":{"type":"array","readOnly":true,"items":{"$ref":"#/components/schemas/CommonError"}},"Info":{"type":"array","readOnly":true,"items":{"$ref":"#/components/schemas/CommonInfo"}},"OpenInfo":{"type":"object","readOnly":true,"additionalProperties":{"type":"string"},"nullable":true}}},"CommonError":{"type":"object","properties":{"ID":{"type":"integer","description":"Numeric error code, e.g. 80 = UnauthorizedUser, 134 = DocumentAlreadyCreated."},"Error":{"type":"string","description":"Error name."},"Paramters":{"type":"string","nullable":true,"description":"Optional context, e.g. \"Row Number - 0\"."}}},"CommonInfo":{"type":"object","properties":{"ID":{"type":"integer"},"Info":{"type":"string"},"Paramters":{"type":"string","nullable":true}}},"GenerelCustomer":{"type":"object","required":["Name"],"description":"One-off (general) customer for documents without a stored customer record.","properties":{"ID":{"type":"integer"},"Name":{"type":"string"},"Identifier":{"type":"string","description":"VAT/ID number."}}},"DocumentItem":{"type":"object","required":["Name","Quantity","Price"],"properties":{"Name":{"type":"string"},"Description":{"type":"string","nullable":true},"Price":{"type":"number","format":"double","description":"Unit price."},"PriceIncludeTax":{"type":"number","format":"double","description":"Price including VAT (when TaxIncluded)."},"Quantity":{"type":"number","format":"double"},"TaxPercentage":{"type":"number","format":"double","nullable":true,"description":"Per-item VAT override."},"Discount":{"$ref":"#/components/schemas/Discount"},"Code":{"type":"string","nullable":true,"description":"Catalog code."},"LawyerIdentifier":{"type":"string","nullable":true,"description":"Lawyer accounts: \"1\" deposits, \"2\" expenses."},"InventoryId":{"type":"integer","nullable":true},"WarehouseId":{"type":"integer","nullable":true},"Total":{"type":"number","format":"double","readOnly":true},"TotalWithoutTax":{"type":"number","format":"double","readOnly":true},"TotalTax":{"type":"number","format":"double","readOnly":true}}},"Discount":{"type":"object","required":["Value"],"properties":{"Value":{"type":"number","format":"double"},"IsNominal":{"type":"boolean","description":"true = fixed amount, false = percent."},"BeforeTax":{"type":"boolean"}}},"Payment":{"type":"object","required":["PaymentType","Amount"],"properties":{"ID":{"type":"integer","description":"Existing payment ID — used for Deposits documents."},"PaymentType":{"type":"integer","description":"1 CreditCard, 2 Check, 3 MoneyTransfer, 4 Cash, 5 Credit, 6 WithholdingTax, 7 Other, 8 Bit, 9 PayBox.","enum":[1,2,3,4,5,6,7,8,9]},"Amount":{"type":"number","format":"double"},"Date":{"type":"string","format":"date-time","nullable":true},"DateStr":{"type":"string","nullable":true,"description":"Alternative string date when Date is not set."},"NumberOfPayments":{"type":"integer","description":"Credit-card installments."},"CreditCardName":{"type":"string","nullable":true,"description":"Card brand name; resolved against configured credit companies."},"CreditCardType":{"type":"integer","nullable":true},"PaymentNumber":{"type":"string","nullable":true,"description":"Check number / last 4 card digits."},"BankName":{"type":"string","nullable":true},"BranchName":{"type":"string","nullable":true},"AccountNumber":{"type":"string","nullable":true},"PayerID":{"type":"string","nullable":true},"ExpirationDate":{"type":"string","nullable":true},"PaymentTypeOtherId":{"type":"integer","description":"Sub-type when PaymentType=7 (Other)."},"PaymentTypeLiteral":{"type":"string","nullable":true}}},"AssociatedEmail":{"type":"object","required":["Mail"],"properties":{"Mail":{"type":"string","format":"email"},"IsUserMail":{"type":"boolean","description":"true marks the copy sent to the account owner."},"ClientId":{"type":"integer","nullable":true},"IsSendDoc":{"type":"boolean","nullable":true}}}}}}
```