EIP-1967 Upgradeable Proxy Standard

EIP-1967 is a standard for implementing upgradeable proxy contracts. This is not the only way to achieve the functionality but it is common. The standard is laid out at https://eips.ethereum.org/EIPS/eip-1967 which provides a template for building these features.

Any contract which conforms to the standard is an upgradeable proxy. And, given the way the standard is structured, it is possible to automatically identify confirming contracts.

This form of automated detection of proxies is available, among other places, for free to the public on many blockchain explorers. Here is an example: https://etherscan.io/address/0x3154cf16ccdb4c6d922629664174b904d80f2c35#readProxyContract.

Under the “Contract” section there are several subsections. Under the “Read as Proxy” subsection you can see this contract has been identified automatically as EIP-1967-compliant and therefore an upgradeable proxy.

This sort of detection should have zero false positives for being an upgradeable proxy (i.e. contracts which are not EIP-1967 compliant should never be identified as compliant). It will, however, have false negatives when applied to contracts which are in fact upgradeable proxies but do this via means other than those laid down in EIP-1967.

It is still possible to determine that a non-EIP-1967 contract is an upgradeable proxy but this requires reading the code.

For EIP-1967-compliant contracts it is safe to rely on the automated tools.