The inventory maximum for each key color is 9999.
Types of Keys
|Picture||Color||Drops from:||Forged from:|
|White Key||Unknown at this point. White keys and vaults will exist in lower income countries. See note below this table.||-|
|Blue Key||Blue Keybooths, Mystery Boxes, Blue Vaults (rare) and Green Vaults (common)||10 White Keys|
|Green Key||Mystery Boxes, Blue Vaults (very rare) and Green Vaults (rare)||10 Blue Keys|
|Yellow Key||Green Vaults (very rare) and Yellow Vaults (rare)||10 Green Keys|
|Red Key||Yellow Vaults (very rare) and Red Vaults (rare)||10 Yellow Keys|
|Purple Key||Red Vaults (very rare) and Purple Vaults (rare)||10 Red Keys|
Regarding the White Key: On August 15, 2021 Kookoopuffs shared on Discord "For lower income countries, we’ll likely have a lower tier of vault. Advertising budgets are scaled to local income levels. But I expect there to be 1 to 2 more tiers below blue that we will deploy in lower income countries."
Players can receive bonus keys from Prize Boxes. Prize boxes come most often from solving vaults, but are also given in some other instances.