The capabilities of a client device largely depend on the amount of available RAM. Traditionally, developers had to use heuristics and either benchmark a device or infer device capabilities based on other factors like the device manufacturer or User Agent strings.

There are two ways to determine the approximate amount of RAM a device has: use the Device Memory JavaScript API or accept Client Hints.

You may query the approximate amount of RAM a device has by retrieving Navigator.deviceMemory

var RAM = navigator.deviceMemory;

You may also use the Client Hints HTTP Header with the Device-Memory directive to retrieve the same approximate RAM capacity.

• Navigator.deviceMemory
• Device-Memory header