Device-Memory
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The Device-Memory
device client hint request header field indicates the approximate amount of available RAM on the client device. The header is part of the Device Memory API.
Header type | Request header, Client hint |
---|---|
Forbidden header name | no |
Note:
- Client Hints are accessible only on secure origins (via TLS).
- A server has to opt in to receive the
Device-Memory
header from the client, by sending theAccept-CH
response header. - Servers that opt in to the
Device-Memory
client hint will typically also specify it in theVary
header. This informs caches that the server may send different responses based on the header value in a request.
Syntax
http
Device-Memory: <number>
Directives
<number>
-
The approximate amount of device RAM. Possible values are:
0.25
,0.5
,1
,2
,4
,8
.
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.
Examples
The server first needs to opt in to receive Device-Memory
header by sending the response headers Accept-CH
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
Specification |
---|
Device Memory # iana-device-memory |
Browser compatibility
BCD tables only load in the browser