Copy as Markdown[Open in ChatGPT](https://chatgpt.com/?q=Read%20https%3A%2F%2Fdocs-docusaurus.kinsta.page%2Fuser-guides%2Frum%2Fsdk-features%2Fanalyze-header-and-payload-data.md%20and%20help%20me%20with%20my%20question%20about%20this%20Coralogix%20documentation%20page.)[Open in Claude](https://claude.ai/new?q=Read%20https%3A%2F%2Fdocs-docusaurus.kinsta.page%2Fuser-guides%2Frum%2Fsdk-features%2Fanalyze-header-and-payload-data.md%20and%20help%20me%20with%20my%20question%20about%20this%20Coralogix%20documentation%20page.)

# Analyzing header and payload data

## Overview[​](#overview "Direct link to Overview")

RUM browser SDK provides advanced data extraction capabilities, allowing you to thoroughly analyze both the headers and payloads of your network requests. By enabling this feature, you gain in-depth insights into your application's communication patterns, including response codes, request metadata, and payload content. This level of detail empowers you to investigate issues with greater precision, enhancing both security and performance. With full access to headers and payloads, you can identify anomalies, debug network behavior effectively, and ensure your application operates seamlessly under all conditions.

## Configuration[​](#configuration "Direct link to Configuration")

To properly monitor network call performance, specify custom rules for capturing network requests and responses using our RUM browser SDK. The `networkExtraConfig` property is an array of configuration objects, each specifying custom rules for capturing network requests and responses. These calls collect data from `Fetch` and `XMLHttpRequest` calls, attaching specified request and response information, headers, and payloads to each network event.

```
CoralogixRum.init({

  networkExtraConfig: [

    {

      url: 'http://example.com',               // Capture requests to this specific URL or regex pattern

      reqHeaders: ['Authorization', 'Content-Type'], // Capture 'Authorization' and 'Content-Type' headers in requests

      resHeaders: ['Cache-Control', 'Date'],   // Capture 'Cache-Control' and 'Date' headers in responses

      collectReqPayload: true,                    // Collect request payload

      collectResPayload: false                    // Do not collect response payload

    },

  ],

});
```

Note

The server must explicitly allow access to specific headers by including them in the `Access-Control-Expose-Headers`response header. Due to limitations in the Fetch and XHR APIs, header retrieval is based on a best-effort approach. As a result, some headers may occasionally be unavailable in the events collected by this integration. Additionally, any payloads exceeding the allowed size will be dropped.