The Vault is a savings feature.

How are chips saved in the Vault?

When playing Sit & Go it is only a percentage of your winnings that are saved in the Vault.
When you play a Cash Game a percentage of your chips from both wins and losses will be saved in your Vault.
When you’ve won first place in a  Spin & Play

The percentage saved per win/loss differs per poker and format.

Levels

Each time you open the vault you will level up until the maximum level 4 is reached. The higher level your Vault is, the more you can fill it up! Here is the exact amount of starting chips and the maximum amount of chips per level:

Level 1 | $330,000 min. | $5,000,000 max.
Level 2 | $650,000 min. | $10,000,000 max.
Level 3 | $1,500,000 min. | $20,000,000 max.
Level 4 | $6,000,000 min. | $60,000,000 max.

Special Vaults

On special occasions, your vault can change into a special vault! The Golden Vault or Black Vault! Make sure you fill it up when the golden or black vault is active since your savings will be multiplied when you use a vault key!

Golden vault: savings x2
Black vault: savings x3

Please note: Your savings will only be multiplied when the Golden or Black vault is active!

How open my Vault?

You can open your vault with a purchase or with a vault Key

Where can I get a Vault key?

You can gain a vault key by opening the biggest reward of the Event calendar, in giveaways on social media, or purchase one in-game

What happens after I used a vault key?

Opening your vault will result in an animation wherein you need to spin the vault handle several times before you get your savings. You can also tab the skip button at the bottom of your screen. The vault will open and you’ll see the number of chips that will be added to your current chips and the number of chips in the vault will reset to the starting amount of the next level until you reach the maximum vault level.

What happens if I purchase a Vault key?

When you purchase the vault key, you will have to open your vault straight away.
If there is an error, you could still open it later by using the vault key. In that case, the price in the "open button" is replaced with “use key”. You can also see unused keys in your inventory under the consumable category.  

Where can I find my Vault?

In the top bar, next to the Lucky Dice icon
If you click it, the vault window will open.