Chain ID
Last updated:
Applies to: EVM chains
In more detail
eth_chainId returns the chain ID as a hex quantity (EIP-695). It is not the same thing as the network ID returned by net_version, although the two are equal on many chains. Well-known chain IDs include Ethereum 1, BNB Smart Chain 56, Polygon PoS 137 and Base 8453; public registries list the rest.
Wallets and signers should always read the chain ID with eth_chainId before signing, rather than trusting a configured value or net_version.