# Define custom headers when doing a POST request

```php
function f4d_modify_http_request_args($parsed_args, $url){
    // Replace XXX with whatever URL you put inside the "Enter a custom form post URL" setting
    // For example if you are doing a post request to https://api.domain.com/create/post
    // replace XXX with that exact URL
    if($url==='XXX'){
        // Update headers, of course you can also alter other arguments if needed
        // Default arguments provided by WordPress: https://github.com/WordPress/wordpress-develop/blob/97218bbfd336035edc9293274fea0f7bd3da85d7/src/wp-includes/class-wp-http.php#L150
        $parsed_args['headers'] = array(
            'Content-Type' => 'application/json; charset=utf-8',
            'ClientID' => 'xxx',
            'Authentication' => 'Basic & Base64 Encoded'
        );
    }
    return $parsed_args;
}
add_filter( 'http_request_args', 'f4d_modify_http_request_args', 10, 2 );
```


---

# 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.super-forms.com/developers/code-examples/define-custom-headers-when-doing-a-post-request.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.