API Changelog – July 6th 2026

Breaking change: invoice_kind field is now mandatory for invoice creation.

Breaking Change: invoice_kind Field is Now Mandatory for Invoice Creation

Following the latest NRS guidelines, the invoice_kind field is now mandatory for all invoice creation requests submitted through the REST API.

Supported Values

The following values are supported for invoice_kind:

• B2C
• B2B
• B2G

Impacted Endpoints

The following invoice creation endpoints now require the invoice_kind field:

• POST /invoices
• POST /app-invoices
• POST /detailed-invoices

Credit & Debit Notes

Credit notes and debit notes will automatically inherit the invoice_kind value from the original invoice. No additional changes are required when creating these document types.

Validation Rules

The API now enforces the following validation rules:

• invoice_kind is mandatory for all REST API invoice creation requests.
• When invoice_kind is set to B2B or B2G, party information is required in the invoice payload.

Note: The invoice_kind field was originally introduced as an optional field in the February API release. This update changes its behavior from optional to mandatory.

Backward Compatibility

Breaking Change

This change is not backward compatible. Existing integrations that create invoices without the invoice_kind field will fail validation until they are updated to include a valid value.