index.md

---

title: Device-Memory
slug: Web/HTTP/Headers/Device-Memory
status:
  - experimental
browser-compat: http.headers.Device-Memory

---

{{HTTPSidebar}} {{SeeCompatTable}} {{securecontext_header}}

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	{{Glossary("Request header")}}, Client hint
{{Glossary("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 the {{HTTPHeader("Accept-CH")}} response header.

• Servers that opt in to the Device-Memory client hint will typically also specify it in the {{HTTPHeader("Vary")}} header. This informs caches that the server may send different responses based on the header value in a request.

Syntax

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 {{HTTPHeader("Accept-CH")}} containing Device-Memory.

Accept-CH: Device-Memory

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

Device-Memory: 1

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Improving user privacy and developer experience with User-Agent Client Hints (web.dev)

• Device Memory API

• {{DOMxRef("Navigator.deviceMemory")}}

• Device client hints

  • {{HTTPHeader("Content-DPR")}}

  • {{HTTPHeader("DPR")}}

  • {{HTTPHeader("Viewport-Width")}}

  • {{HTTPHeader("Width")}}

• {{HTTPHeader("Accept-CH")}}

• HTTP Caching > Varying responses and {{HTTPHeader("Vary")}}