Device-Memory header

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.

Warning: The Device-Memory header was standardized as Sec-CH-Device-Memory and the new name is now preferred.

The HTTP Device-Memory request header is used in device client hints to indicate the approximate amount of available RAM on the client device, in gigabytes. The header is part of the Device Memory API.

Client hints are accessible only on secure origins. A server has to opt in to receive the Device-Memory header from the client, by first sending the Accept-CH response header. Servers that opt in to the Device-Memory client hint will typically also specify it in the Vary header to inform caches that the server may send different responses based on the header value in a request.

Header type	Request header, Client hint
Forbidden request header	No

Syntax

http

Device-Memory: <number>

Directives

<number>

The approximate amount of device RAM.

The amount of device RAM can be used as a fingerprinting variable, so values for the header are intentionally coarse to reduce the potential for its misuse. Values are only reported in powers of two, and are clamped to an implementation-defined minimum lower value and a maximum upper value. These bounds may change over time (see browser compatibility table).

For example, if a browser does not report below 2 or above 32 then the value is one of: 2, 4, 8, 16, 32.

Examples

The server first needs to opt in to receive Device-Memory header by sending the Accept-CH response header containing Device-Memory:

http

Accept-CH: Device-Memory

Then on subsequent requests the client might send Device-Memory header back:

http

Device-Memory: 1

Specifications

This feature does not appear to be defined in any specification.

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`Device-Memory` request header Deprecated Non-standard	Chrome – Full support Chrome 61 (Release date: 2017-09-05) footnote footnote From Chrome 147, reported values are 2, 4, 8, 16, and 32. footnote Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	Edge – Full support Edge 79 (Release date: 2020-01-15) footnote footnote From Edge 147, reported values are 2, 4, 8, 16, and 32. footnote Before Edge 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	Firefox – No support Firefox footnote No support	Opera – Full support Opera 48 (Release date: 2017-09-27) footnote footnote From Opera 131, reported values are 2, 4, 8, 16, and 32. footnote Before Opera 131, reported values were 0.25, 0.5, 1, 2, 4, and 8.	Safari – No support Safari footnote No support	Chrome Android – Full support Chrome Android 61 (Release date: 2017-09-05) footnote footnote From Chrome 147, reported values are 1, 2, 4, and 8. footnote Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	Firefox for Android – No support Firefox for Android footnote No support	Opera Android – Full support Opera Android 45 (Release date: 2018-02-15) footnote footnote From Chrome 147, reported values are 1, 2, 4, and 8. footnote Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – Full support Samsung Internet 8 (Release date: 2018-07-18) footnote footnote From Chrome 147, reported values are 1, 2, 4, and 8. footnote Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	WebView Android – Full support WebView Android 61 (Release date: 2017-09-05) footnote footnote From Chrome 147, reported values are 1, 2, 4, and 8. footnote Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Non-standard. Check cross-browser support before using.
: Deprecated. Not for use in new websites.
: See implementation notes.

Device-Memory header

Syntax

Directives

Examples

Specifications

Browser compatibility

Legend

See also