> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gobl.org/llms.txt
> Use this file to discover all available pages before exploring further.
# EN 16931-1:2017
Key: `eu-en16931-v2017`
Support for the European Norm (EN) 16931-1:2017 standard for electronic invoicing.
This addon ensures the basic rules and mappings are applied to the GOBL document
ensure that it is compliant and easily convertible to other formats.
We strongly recommend checking the output and specifically the extension codes
used to ensure that any assumptions do not need be adjusted.
## Tax Code Extension Mappings
The following tables show how GOBL tax keys/categories are mapped to UNTDID 5305 tax category codes:
### VAT
| GOBL Tax Key | UNTDID 5305 Code | Description |
| --------------- | ---------------- | ---------------------- |
| standard | S | Standard rate |
| zero | Z | Zero rated goods |
| exempt | E | Exempt from tax |
| reverse-charge | AE | VAT Reverse Charge |
| intra-community | K | Intra-community supply |
| export | G | Export outside the EU |
| outside-scope | O | Not subject to VAT |
### Other
For Spanish special territories, **IGIC** (Canary Islands) maps to code **L** and **IPSI** (Ceuta and Melilla) maps to code **M**.
Any other tax category defaults to UNTDID 5305 code **O** (Outside Scope).
## Exemption Notes
Exempt tax categories (E, AE, K, G, O) require either a CEF VATEX code
(`cef-vatex`) on the tax combo, or an exemption note in `tax.notes`.
Exemption notes use the `tax.Note` struct with `cat`, `key`, and `text` fields.
During normalization, the note's `key` is mapped to the corresponding
`untdid-tax-category` extension (e.g. `exempt` → `E`,
`reverse-charge` → `AE`).
Each exempt tax category without a VATEX code must have at least one
exemption note covering it.
## Scenarios
### bill/invoice
**Filters:**
* **Types:** `standard`
**Output:**
* **Extensions:** `untdid-document-type:380`
**Filters:**
* **Types:** `credit-note`
**Output:**
* **Extensions:** `untdid-document-type:381`
**Filters:**
* **Types:** `debit-note`
**Output:**
* **Extensions:** `untdid-document-type:383`
**Filters:**
* **Types:** `corrective`
**Output:**
* **Extensions:** `untdid-document-type:384`
**Filters:**
* **Types:** `proforma`
**Output:**
* **Extensions:** `untdid-document-type:325`
**Filters:**
* **Types:** `standard`
* **Tags:** `partial`
**Output:**
* **Extensions:** `untdid-document-type:326`
**Filters:**
* **Types:** `standard`
* **Tags:** `self-billed`
**Output:**
* **Extensions:** `untdid-document-type:389`
**Filters:**
* **Types:** `credit-note`
* **Tags:** `self-billed`
**Output:**
* **Extensions:** `untdid-document-type:261`
**Filters:**
* **Types:** `standard`
* **Tags:** `prepayment`
**Output:**
* **Extensions:** `untdid-document-type:386`
**Filters:**
* **Types:** `standard`
* **Tags:** `factoring`
**Output:**
* **Extensions:** `untdid-document-type:393`
**Filters:**
* **Types:** `credit-note`
* **Tags:** `factoring`
**Output:**
* **Extensions:** `untdid-document-type:396`
## Validation Rules
| Field | Test | Validation Code / Message |
| ---------------------- | ----------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- |
| Invoice | | `GOBL-EU-EN16931-BILL-INVOICE-08`
Exempt tax categories require either a VATEX code or an exemption note |
| `tax` | | `GOBL-EU-EN16931-BILL-INVOICE-01`
Tax details are required with ext and UNTDID document type |
| `tax.ext` | - Ext require \[untdid-document-type]
| `GOBL-EU-EN16931-BILL-INVOICE-02`
Document type extension is required |
| `lines` | | `GOBL-EU-EN16931-BILL-INVOICE-03`
At least one line is required (BR-16) |
| `supplier.addresses` | | `GOBL-EU-EN16931-BILL-INVOICE-04`
Supplier addresses are required (BR-8) |
| `customer.addresses` | | `GOBL-EU-EN16931-BILL-INVOICE-05`
Customer addresses are required (BR-10) |
| `payment` | - Is due standard invoice
- Present
| `GOBL-EU-EN16931-BILL-INVOICE-06`
Payment details are required when amount is due (BR-CO-25) |
| `payment.terms` | - Is due standard invoice
- Present
| `GOBL-EU-EN16931-BILL-INVOICE-07`
Payment terms are required when amount is due (BR-CO-25) |
| Field | Test | Validation Code / Message |
| ----------------------- | --------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| Discount | | `GOBL-EU-EN16931-BILL-DISCOUNT-02`
Either a reason or an allowance type extension is required (BR-33) |
| `taxes` | | `GOBL-EU-EN16931-BILL-DISCOUNT-01`
Taxes are required (BR-32) |
| Field | Test | Validation Code / Message |
| --------------------------- | ------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------- |
| LineDiscount | | `GOBL-EU-EN16931-BILL-LINEDISCOUNT-01`
Either a reason or an allowance type extension is required (BR-41) |
| Field | Test | Validation Code / Message |
| --------------------- | ---------------------------------------------------- | ---------------------------------------------------------------------------------------------------- |
| Charge | | `GOBL-EU-EN16931-BILL-CHARGE-01`
Either a reason or a charge type extension is required (BR-36) |
| Field | Test | Validation Code / Message |
| ------------------------- | ---------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| LineCharge | | `GOBL-EU-EN16931-BILL-LINECHARGE-01`
Either a reason or a charge type extension is required (BR-44) |
| Field | Test | Validation Code / Message |
| ----- | ----------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| `ext` | - Ext require \[untdid-payment-means]
| `GOBL-EU-EN16931-PAY-INSTRUCTIONS-01`
Payment means extension is required (BR-49) |
| Field | Test | Validation Code / Message |
| -------------------- | ---------------------------------------------------------- | ------------------------------------------------------------------------------------------ |
| Terms | | `GOBL-EU-EN16931-PAY-TERMS-01`
Either due\_dates or notes must be provided (BR-CO-25) |
| Field | Test | Validation Code / Message |
| ------ | --------------------------------------------------------------------- | ----------------------------------------------------------- |
| `unit` | | `GOBL-EU-EN16931-ORG-ITEM-01`
Unit is required (BR-23) |
| Field | Test | Validation Code / Message |
| ------ | --------------------------------------------------------------------- | --------------------------------------------------------- |
| `code` | | `GOBL-EU-EN16931-ORG-ATTACHMENT-01`
Code is required |
| Field | Test | Validation Code / Message |
| --------- | ---------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| `inboxes` | | `GOBL-EU-EN16931-ORG-PARTY-01`
Cannot have more than one inbox (BT-34, BT-49) |
| Field | Test | Validation Code / Message |
| -------------------- | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------ |
| Inbox | - Scheme required with code
| `GOBL-EU-EN16931-ORG-INBOX-01`
Scheme cannot be blank when code is set (BR-62, BR-63) |
| Inbox | - Code required with scheme
| `GOBL-EU-EN16931-ORG-INBOX-02`
Code cannot be blank when scheme is set |
| Field | Test | Validation Code / Message |
| --------- | --------------------------------------------------------------------- | ------------------------------------------------------------------------------------- |
| `country` | | `GOBL-EU-EN16931-ORG-ADDRESS-01`
Country is required (BR-9, BR-11, BR-20, BR-57) |
| Field | Test | Validation Code / Message |
| ----- | ------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| `ext` | - Ext require \[untdid-tax-category]
| `GOBL-EU-EN16931-TAX-COMBO-01`
Tax category extension is required |
| `ext` | - Is VAT
- Ext 'untdid-tax-category' in \[AE, E, G, K, O, S, Z]
| `GOBL-EU-EN16931-TAX-COMBO-02`
VAT category code must be valid |
| `ext` | - Is IGIC
- Ext 'untdid-tax-category' in \[L]
| `GOBL-EU-EN16931-TAX-COMBO-03`
Must use IGIC category code |
| `ext` | - Is IPSI
- Ext 'untdid-tax-category' in \[M]
| `GOBL-EU-EN16931-TAX-COMBO-04`
Must use IPSI category code |
| `ext` | - Is outside scope
- Ext 'untdid-tax-category' in \[O]
| `GOBL-EU-EN16931-TAX-COMBO-05`
Must use outside scope category code |
| `ext` | - Is exempt
- Ext require \[cef-vatex]
| `GOBL-EU-EN16931-TAX-COMBO-06`
VATEX extension is required for exempt tax (BR-E-10) |
| `ext` | - Is non-exempt
- Ext exclude \[cef-vatex]
| `GOBL-EU-EN16931-TAX-COMBO-07`
VATEX extension must not be set for standard, zero, IGIC, or IPSI categories (BR-S-10, BR-Z-10) |