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POST
cURL

Authorizations

X-Api-Key
string
header
required

Your fat_… integration key. Create one in Settings → Integrations → API Keys.

Body

documentType
enum<string>
required

Document identity. Invoice and CreditNote are standard tax documents; the SelfBilling* variants are issued by the buyer on the supplier's behalf. On /v1/credit-notes endpoints, CreditNote is applied regardless of the value sent.

Available options:
Invoice,
CreditNote,
SelfBillingInvoice,
SelfBillingCreditNote
Example:

"Invoice"

invoiceNumber
string | null
required
issueDate
string<date>
required
dueDate
string<date> | null
required
currency
string | null
required
seller
object
required
buyer
object
required
lines
object[]
required
references
object | null
required
notes
string | null
required
precedingInvoiceNumber
string | null
required
taxTotal
object | null
allowancesCharges
any[] | null
additionalDocuments
object[] | null
delivery
object | null
transactionType
object | null
beneficiaryId
string | null
principalId
string | null
billingFrequencyCode
string | null
taxCurrencyCode
string | null
currencyExchangeRate
number<double> | null
paymentMode
string | null

Payment means: a UNCL4461 code (e.g. 10 = cash, 20 = cheque, 30 = credit transfer, 48 = bank card, 49 = direct debit) or one of the aliases "cash", "cheque", "card", "debit". Defaults to 30 (credit transfer); without a paymentBankAccount, 30 falls back to 1 (instrument not defined).

Example:

"30"

paymentTerms
string | null
paymentBankAccount
string | null
vatPointDate
string<date> | null
billingPeriodStart
string<date> | null
billingPeriodEnd
string<date> | null
precedingInvoiceIssueDate
string<date> | null
prepaidAmount
number<double> | null

Response

Created

id
string
required
invoiceNumber
string
required
status
enum<string>
required

Document status: Draft (created, not submitted), Pending (queued or being delivered over Peppol), Sent (delivered), DeliveryFailed (submission failed — see submissionError), Received (inbound purchase document).

Available options:
Draft,
Pending,
Sent,
DeliveryFailed,
Received
Example:

"Draft"

participantDelivery
enum<string>
required

Peppol delivery indicator: Pending (delivery in flight or awaiting confirmation), Failed (delivery failed), NotApplicable (not submitted, e.g. a Draft).

Available options:
Pending,
Failed,
NotApplicable
Example:

"NotApplicable"

createdAt
string
required
submissionError
string | null