UUPS Proxy Standard

The Universal Upgradeable Proxy Standard (UUPS) is an efficient proxy pattern where the upgrade logic resides in the implementation contract rather than the proxy contract itself. By moving the upgrade function to the implementation, the proxy remains lightweight, reducing gas costs for users.

This standard is considered more gas-efficient than traditional proxy patterns and provides greater flexibility in how upgrades are managed. However, because the upgrade logic is in the implementation, it is critical to ensure that the implementation is initialized correctly and that the upgrade function is properly protected.

If the upgrade function is missing or insecure, the proxy can become permanently locked or hijacked. The UUPS standard has become a preferred choice for many developers due to its balance of efficiency and upgradeability.