# URL

Similar to Email, an URL can also be passed as a string. The URL format is derived from the [HTML 5.1-Forms Email syntax](https://www.w3.org/TR/2016/REC-html51-20161101/sec-forms.html#email-state-typeemail) recommended by W3C.

URL format follows the syntax specified in the [HTML 5.1 W3C recommendation under section 4.10.5.1.4.](https://www.w3.org/TR/2016/REC-html51-20161101/sec-forms.html#email-state-typeemail)

The code snippet shows how to define an `url` In the Internet Object Document.

```yaml
# Defining an url
website: url
---
https://example.com

```

{% hint style="info" %}
In the case of the `url` format, the data must be valid URL.
{% endhint %}

```yaml
# valid and Invaliid url
website: url
---

https://example.com # the input will be accepted by the IO parser

Example.com # input will not be accepted as it is not a valid url 

```

### MemberDef

The Email is derived from the String type, hence it shares the same [MemberDef](/schema-definition-language/data-types/string.md#memberdef) as the String. However, URL enforces additional constraints with the respective url format.

#### **Choices**

The `choices` can be added to member variables in the `url` so that it is restricted to the fixed set of available choices. Choices must be an array of valid `url`. The code snippet here shows how to add choices for the url.

```yaml
# Set the choices for companyWeburl
companyWeburl: {
  type: url, 
    choices: [https://example1.com, 
     https://example2.com, https://example3.com]           
}
---
https://example1.com
```

#### pattern

User may specify `pattern` for the `url` by defining `pattern` as,

```yaml
# Set pattern for the referenceUrl
referenceUrl: {
  type: url, 
   pattern: 'https?://(?:[-\w.]|(?:%[\da-fA-F]{2}))+'
 }
---
http://example.com, http://example2.com
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.internetobject.org/schema-definition-language/data-types/string/string-derived-types/url.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.