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Device-Memory

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

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The Device-Memory header is a Device Memory API header that works like Client Hints header which represents the approximate amount of RAM client device has.

Note: Client Hints are accessible only on secure origins (via TLS). Server has to opt in to receive Device-Memory header from the client by sending Accept-CH and Accept-CH-Lifetime response headers.

Syntax

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. The header takes on the following values: 0.25, 0.5, 1, 2, 4, 8.

Device-Memory: <number>

Examples

Server first needs to opt in to receive Device-Memory header by sending the response headers Accept-CH containing Device-Memory and Accept-CH-Lifetime.

Accept-CH: Device-Memory
Accept-CH-Lifetime: 86400

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

Device-Memory: 1

Specifications

Specification Status Comment
Device Memory 1
The definition of 'Device-Memory' in that specification.
Editor's Draft Initial definition.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Device-Memory 61 ≤79 ? ? 48 ?
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
Device-Memory 61 61 ? ? ? 8.0

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Device-Memory