TripMode automatically reduces your data usage when you are on a mobile hotspot, or on an expensive and limited network.
When TripMode is ON, it prevents all your apps from accessing the Internet but those that have been whitelisted by yourself. It typically stops automatic updates, online backups, Photos syncs, and various obscure apps from consuming precious data. Both uploads and downloads are blocked.
Your Mac doesn’t care whether you are using a sluggish hotspot, crippled hotel/coffee-shop/airport Wi-Fi, or a blazing fast network. Plenty of background apps will aggressively keep trying to download content and updates from the Internet, slowing down your Internet speed to a crawl. TripMode stops that by allowing you to grant your Internet bandwidth to only the apps that you need.
Can I use TripMode with any Wi-Fi or Ethernet network, 3G/4G dongle, or Mi-Fi device?
Yes. Just turn TripMode ON from the topbar. TripMode should activate itself each time your Mac connects to that network.