Secure context

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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.

Header type Request header
Forbidden header name ?

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.


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>


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


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

Browser compatibility

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See also