Boosts multiply your in-game earnings, even when you're offline. You can buy them in the in-game shop and earn them from in-game features/events like Expeditions and Event Mines. There's a wide variety of boosts available, with new ones rotating daily in the shop. You can also try a "Mystery Boost" to win a random boost from a pre-determined pool.

Your boost inventory is located at the bottom of your game screen while in a mine, next to the shop icon.

There are also two types of permanent boosts available for purchase: "Double Cash forever" and "Double Idle Cash forever". These can work together:

• With both active, you'll see Idle Cash as 4x and Cash as x2
• With "Double Cash" only, you'll see Idle Cash as x2 and Cash as x2
• With "Double Idle Cash" only, you'll see Idle Cash x2