The HTTP Device-Memory header is a request header field that is part of the client hints platform. It provides the server with information about the amount of available memory on the client.
The HTTP Device-Memory header is an experimental technology that serves as a client hint. It provides the server with information about the amount of available memory on the client and is only available in a secure context (HTTPS).
A server is required to opt-in to receive the device-memory information and does so using the Accept-CH header.
The directive is a number that represents the number of gigabytes of RAM. The list of possible values is 0.25 (250 megabytes), 0.5 (500 megabytes), 1 (1 gigabyte), 2, 4, and 8.
In this example, the client is informing the server that it has approximately two gigabytes of available RAM.
The HTTP Device-Memory header is part of the Client Hints architecture and informs the server concerning how much memory the client device has available.