Web/API/PerformanceResourceTiming

The PerformanceResourceTiming interface enables retrieval and analysis of detailed network timing data regarding the loading of an application's resources. An application can use the timing metrics to determine, for example, the length of time it takes to fetch a specific resource, such as an XMLHttpRequest, <SVG>, image, or script.

The interface's properties create a resource loading timeline with high-resolution timestamps for network events such as redirect start and end times, fetch start, DNS lookup start and end times, response start and end times, etc.. Additionally, the interface extends PerformanceEntry with other properties which provide data about the size of the fetched resource as well as the type of resource that initiated the fetch.

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Note: This feature is available in Web Workers.

Properties

This interface extends the following PerformanceEntry properties for resource performance entry types by qualifying and constraining them as follows:

 PerformanceEntry.entryTypeRead only

Returns "resource".

PerformanceEntry.nameRead only

Returns the resources URL.

PerformanceEntry.startTimeRead only

Returns the timestamp for the time a resource fetch started. This value is equivalent to PerformanceEntry.fetchStart.

PerformanceEntry.durationRead only

Returns a timestamp that is the difference between the responseEnd and the startTime properties.

The interface also supports the following properties which are listed in the order in which they are recorded for the fetching of a single resource. An alphabetical listing is shown in the navigation, at left.

PerformanceResourceTiming.initiatorTypeRead only

A string representing the type of resource that initiated the performance entry, as specified in PerformanceResourceTiming.initiatorType.

PerformanceResourceTiming.nextHopProtocolRead only

A string representing the network protocol used to fetch the resource, as identified by the ALPN Protocol ID (RFC7301).

PerformanceResourceTiming.workerStartRead only

Returns a DOMHighResTimeStamp immediately before dispatching the FetchEvent if a Service Worker thread is already running, or immediately before starting the Service Worker thread if it is not already running. If the resource is not intercepted by a Service Worker the property will always return 0.

PerformanceResourceTiming.redirectStartRead only

A DOMHighResTimeStamp that represents the start time of the fetch which initiates the redirect.

PerformanceResourceTiming.redirectEndRead only

A DOMHighResTimeStamp immediately after receiving the last byte of the response of the last redirect.

PerformanceResourceTiming.fetchStartRead only

A DOMHighResTimeStamp immediately before the browser starts to fetch the resource.

PerformanceResourceTiming.domainLookupStartRead only

A DOMHighResTimeStamp immediately before the browser starts the domain name lookup for the resource.

PerformanceResourceTiming.domainLookupEndRead only

A DOMHighResTimeStamp representing the time immediately after the browser finishes the domain name lookup for the resource.

PerformanceResourceTiming.connectStartRead only

A DOMHighResTimeStamp immediately before the browser starts to establish the connection to the server to retrieve the resource.

PerformanceResourceTiming.connectEndRead only

A DOMHighResTimeStamp immediately after the browser finishes establishing the connection to the server to retrieve the resource.

PerformanceResourceTiming.secureConnectionStartRead only

A DOMHighResTimeStamp immediately before the browser starts the handshake process to secure the current connection.

PerformanceResourceTiming.requestStartRead only

A DOMHighResTimeStamp immediately before the browser starts requesting the resource from the server.

PerformanceResourceTiming.responseStartRead only

A DOMHighResTimeStamp immediately after the browser receives the first byte of the response from the server.

PerformanceResourceTiming.responseEndRead only

A DOMHighResTimeStamp immediately after the browser receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first.

PerformanceResourceTiming.transferSizeRead only

A number representing the size (in octets) of the fetched resource. The size includes the response header fields plus the response payload body.

PerformanceResourceTiming.encodedBodySizeRead only

A number representing the size (in octets) received from the fetch (HTTP or cache), of the payload body, before removing any applied content-codings.

PerformanceResourceTiming.decodedBodySizeRead only

A number that is the size (in octets) received from the fetch (HTTP or cache) of the message body, after removing any applied content-codings.

PerformanceResourceTiming.serverTimingRead only

An array of PerformanceServerTiming entries containing server timing metrics.

Methods

PerformanceResourceTiming.toJSON()

Returns a DOMString that is the JSON representation of the PerformanceResourceTiming object.

Example

See the example in Using the Resource Timing API.

Specifications

Specification	Status	Comment
Resource Timing Level 1The definition of 'PerformanceResourceTiming' in that specification.	Candidate Recommendation	Initial definition.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
PerformanceResourceTiming	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE Full support 10	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
connectEnd	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE Full support 10	Opera Full support 32	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 32	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
connectStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE Full support 10	Opera Full support 32	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 32	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
decodedBodySize	Chrome Full support 54	Edge Full support 17	Firefox Full support 45	IE No support No	Opera Full support 41	Safari No support No	WebView Android Full support 54	Chrome Android Full support 54	Firefox Android Full support 45	Opera Android Full support 41	Safari iOS No support No	Samsung Internet Android Full support 6.0
domainLookupEnd	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
domainLookupStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
encodedBodySize	Chrome Full support 54	Edge Full support 17	Firefox Full support 45	IE No support No	Opera Full support 41	Safari No support No	WebView Android Full support 54	Chrome Android Full support 54	Firefox Android Full support 45	Opera Android Full support 41	Safari iOS No support No	Samsung Internet Android Full support 6.0
fetchStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
initiatorType	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
nextHopProtocol	Chrome Full support 61	Edge Full support 17	Firefox Full support 45	IE No support No	Opera No support No	Safari No support No	WebView Android Full support 61	Chrome Android Full support 61	Firefox Android Full support 45	Opera Android No support No	Safari iOS No support No	Samsung Internet Android Full support 8.0
redirectEnd	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
redirectStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
requestStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
responseEnd	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
responseStart	Chrome Full support 43	Edge Full support 12	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
secureConnectionStart	Chrome Full support 43	Edge Full support 18	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
serverTiming	Chrome Full support 65	Edge Full support ≤79	Firefox Full support 61	IE No support No	Opera Full support 52	Safari No support No	WebView Android Full support 65	Chrome Android Full support 65	Firefox Android Full support 61	Opera Android Full support 47	Safari iOS No support No	Samsung Internet Android Full support 9.0
toJSON	Chrome Full support 43	Edge Full support ≤18	Firefox Full support 40	IE No support No	Opera Full support 30	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 42	Opera Android Full support 30	Safari iOS Full support 11	Samsung Internet Android Full support 4.0
transferSize	Chrome Full support 54	Edge Full support 17	Firefox Full support 45	IE No support No	Opera Full support 41	Safari No support No	WebView Android Full support 54	Chrome Android Full support 54	Firefox Android Full support 45	Opera Android Full support 41	Safari iOS No support No	Samsung Internet Android Full support 6.0
Available in workers	Chrome Full support 43	Edge Full support ≤18	Firefox Full support 60	IE No support No	Opera Full support 32	Safari Full support 12	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 60	Opera Android Full support 32	Safari iOS No support No	Samsung Internet Android Full support 4.0
workerStart	Chrome Full support 43	Edge Full support 16	Firefox Full support 58	IE No support No	Opera Full support 32	Safari Full support 11	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 58	Opera Android Full support 32	Safari iOS Full support 11	Samsung Internet Android Full support 4.0

Legend

Full support  

Full support

No support  

No support

See also

• Resource Timing (Overview)
• Using the Resource Timing API

PerformanceResourceTiming by Mozilla Contributors is licensed under CC-BY-SA 2.5.