> ## 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.

# Attachment

An Attachment provides a structure to be used to attach documents inside a GOBL document, either as a reference via a URL, or directly as a base64 encoded string.

## Schema ID

`https://gobl.org/draft-0/org/attachment`

## Properties

| Title       | Property      | Type                                | Description                                                                            |
| ----------- | ------------- | ----------------------------------- | -------------------------------------------------------------------------------------- |
| UUID        | `uuid`        | string                              | Universally Unique Identifier.                                                         |
| Key         | `key`         | [cbc.Key](/draft-0/cbc/key)         | Key used to identify the attachment inside the document.                               |
| Code        | `code`        | [cbc.Code](/draft-0/cbc/code)       | Code used to identify the payload of the attachment.                                   |
| Name        | `name`        | string                              | Filename of the attachment, will override name retrieved from URL.                     |
| Description | `description` | string                              | Details of why the attachment is being included and details on what it contains.       |
| URL         | `url`         | string                              | URL of where to find the attachment.                                                   |
| Digest      | `digest`      | [dsig.Digest](/draft-0/dsig/digest) | Digest is used to verify the integrity of the attachment when downloaded from the URL. |
| MIME Type   | `mime`        | string                              | MIME type of the attachment.                                                           |

## Validation Rules

| Field  | Test                                                                                                                                                                                                              | Validation Code / Message                                                                                 |
| ------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- |
| `url`  | <ul class="gobl-test"><li class="gobl-test-present">Present</li><li>Url</li></ul>                                                                                                                                 | `GOBL-ORG-ATTACHMENT-01`<br />Attachment URL must be valid                                                |
| `mime` | <ul class="gobl-test"><li>One of \[application/pdf, image/jpeg, image/png, text/csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.oasis.opendocument.spreadsheet]</li></ul> | `GOBL-ORG-ATTACHMENT-02`<br />Attachment MIME type must be of an expected types defined in EN16931-1:2017 |