> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lantern.is/llms.txt
> Use this file to discover all available pages before exploring further.

# birth_date

> Access the customer's birth date for personalized experiences and birthday campaigns.

## Syntax

<Tabs>
  <Tab title="Liquid">
    ```liquid theme={null}
    customer.metafields.facts.birth_date
    ```
  </Tab>
</Tabs>

## Description

The `birth_date` metafield contains the customer's birth date in ISO format (YYYY-MM-DD). This data can be used for birthday campaigns, age-based promotions, and personalized experiences.

<Info>
  Birth date uses the `facts` namespace (not `lantern`) and follows ISO 8601 date format.
</Info>

## Properties

**Type:** `Date (ISO 8601 String)`
**Namespace:** `facts`

## Return Values

| Scenario            | Value                              | Type   |
| ------------------- | ---------------------------------- | ------ |
| Birth date provided | Date string (e.g., `"1990-05-15"`) | String |
| No birth date       | `null`                             | null   |
| Logged out          | `null`                             | null   |

## Examples

### Basic Birthday Display

```liquid theme={null}
{% assign birth_date = customer.metafields.facts.birth_date %}
{% if birth_date %}
  {% assign birthday = birth_date | date: '%B %d' %}
  <p>Birthday: {{ birthday }}</p>
{% endif %}
```