Real User Monitoring Metrics

This page lists all the metric that are reported by DebugBear's Real User Monitoring (RUM) feature. Use the API ID to access these metrics via the DebugBear API.

Available RUM metrics

DebugBear RUM currently supports 31 different metrics.

Time to First Byte

API ID: ttfb

The Full Time to First Byte measures how quickly the server responds to the HTML document request. This includes time spent establishing a server connection or on redirects. More details.

First Contentful Paint

API ID: fcp

First Contentful Paint measures how quickly content appears on the page after navigation. For example, text and images count as content. More details.

Largest Contentful Paint

API ID: lcp

Largest Contentful Paint measures how quickly the largest page element appears. This could be a hero image or a big heading. More details.

Cumulative Layout Shift

API ID: cls

Cumulative Layout Shift measures how stable the page layout is. Layout instability is when content shifts around on the page after being rendered. More details.

Interaction to Next Paint

API ID: inp

Interaction to Next Paint measures how quickly the page updates after the user interacts with it. Chrome User Experience Report (CrUX) data is collected by Google from real Chrome users. CrUX metrics are aggregated over the previous 28 days, so they don't respond to changes to the website as quickly as lab metrics. More details.

DOMContentLoaded Event

API ID: dcl

The DOMContentLoaded event timing measure when the initial page HTML has been parsed. This milestone occurs before dependent resources like async scripts or images are loaded. More details.

Load Event

API ID: load

The load event marks the time when the page has loaded including any dependent resources like scripts and images. While the Load event has long been used as a page speed metric, it was not designed to be one. Where possible, prefer a paint timing metric like FCP or LCP. More details.

TTFB Redirect

API ID: ttfbRedirect

Time spent on same-origin redirects, for example if example.com/a returns a 301 status code and redirects to example.com/b. More details.

TTFB Other

API ID: ttfbWait

Various wait times, for example service worker processing or cross-origin redirects. More details.

TTFB DNS

API ID: ttfbDns

Time spent looking up the IP address for the domain name. More details.

TTFB TCP

API ID: ttfbTcp

Time spent establishing a reliable connection. More details.

TTFB SSL

API ID: ttfbSsl

Time spent establishing a secure connection. More details.

TTFB Response

API ID: ttfbResponse

Time spent waiting for the server to respond with the HTML document content. More details.

TTFB Download

API ID: ttfbDownload

Time spent downloading the HTML document More details.

LCP Render Delay

API ID: lcpRenderDelay

The render delay measures how long it takes for the LCP element to become visible. More details.

LCP Load Duration

API ID: lcpLoadTime

If the LCP element is an image the resource load time measures how long it takes to request and download the image. More details.

LCP Load Delay

API ID: lcpLoadDelay

If the LCP element is an image the load delay measures how long after the document TTFB the image resource is discovered by the browser. More details.

Input Delay

API ID: inputDelay

The Input Delay component of the Interaction to Next Paint metric measures how much time elapses between the interaction and when the browser starts processing the event.

A high input delay suggests that background tasks may delay interaction processing. More details.

Processing Time

API ID: processingTime

The Processing Time component of the Interaction to Next Paint metric measures how long it takes to run the JavaScript event handlers that handle the event. More details.

Presentation Delay

API ID: presentationDelay

The Presentation Delay component of the Interaction to Next Paint metric measures how soon after an interaction the main thread becomes idle and the browser can display the next rendering frame.

A high presentation delay can suggest complex rendering logic or a series of queued-up user interactions. More details.

First-Party Page Weight

API ID: fppwTotal

Download size for first-party requests on the page.

Browsers can't consistently report third-party resource sizes.

If resources are served from the browser cache this will result in a smaller page weight. More details.

Browser Uncached Ratio

API ID: uncachedRatio

Percentage of requests that were served from a server rather than the browser cache. More details.

Error Count

API ID: errorCount

The number of unhandled errors and promise rejections that were recorded.

Network RTT

API ID: networkRtt

Rough round trip time (RTT) estimate that the browser provides through the Network Information API. More details.

Network Bandwidth

API ID: networkBandwidth

Rough bandwidth estimate that the browser provides through the Network Information API.

Page View Count

API ID: views

The number of times page views for each item matching a category.