> ## Documentation Index
> Fetch the complete documentation index at: https://gobl-cli-install-gobl-dev.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Stamp

Stamp defines an official seal of approval from a third party like a governmental agency or intermediary and should thus be included in any official envelopes.

## Schema ID

`https://gobl.org/draft-0/head/stamp`

## Properties

| Title | Property | Type | Description |
| - | - | - | - |
| Provider | `prv` | [cbc.Key](/draft-0/cbc/key) | Identity of the agency used to create the stamp usually defined by each region. |
| Value | `val` | string | The serialized stamp value generated for or by the external agency |

## Validation Rules

| Field | Test | Validation Code / Message |
| - | - | - |
| `prv` | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-HEAD-STAMP-01`<br />Stamp provider is required |
| `val` | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-HEAD-STAMP-02`<br />Stamp value is required |


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