EIP155 Namespace, aka EVM Chains - Addresses

Author Simon Warta, ligi, Pedro Gomes, Antoine Herzog, Joel Thorstensson
Discussions-To https://github.com/ChainAgnostic/namespaces/pull/2
Status Draft
Type Standard
Created 2019-12-05
Updated 2022-03-27
Requires CAIP-2, CAIP-10
Withdrawal reason CAIP-3


For context, see the CAIP-10 specification.


While Ethereum “accounts” were the unstated norm in the definition of CAIP-10, there are still some particularities of the syntax that should be specified for the unfamiliar.


Ethereum addresses were, historically, case-insensitive and normalized to use all-lowercase letters (abcdef) like most hexadecimal numeric types. With the ratification of EIP55, however, a particular normalization of lowercase- and uppercase- abcdefABCDEF characters was invented as an efficient form of checksum. See EIP55 for specification.

Backwards Compatibility

An earlier version of the CAIP-10 schema was defined by appending as suffix the CAIP-2 chainId delimited by the at sign (@), i.e. 0x22227A31dd842196A246d8f3b775998560eAa61d@eip155:1 in the above example. This was changed Aug 11, 2021 and some systems built against the earlier drafts may present accounts in this manner.

Test Cases

# Ethereum mainnet (valid/checksummed)

# Ethereum mainnet (will not validate in EIP155-conformant systems)

# Polygon mainnet (valid/checksummed)

# Polygon mainnet (will not validate in EIP155-conformant systems)


  • EIP155: Ethereum Improvement Proposal specifying generation and validation of ChainIDs
  • [ethereum-lists/chains][]: An open registry for eip155 network operators to claim a unique chainID and self-publish RPC/node information for them.
  • ERC20: Basic [aka Fungible] Token Standard
  • ERC721: Non-Fungible Token Standard


Copyright and related rights waived via CC0.


Please cite this document as:

Simon Warta, ligi, Pedro Gomes, Antoine Herzog, Joel Thorstensson, "namespaces/eip155-caip10: EIP155 Namespace, aka EVM Chains - Addresses [DRAFT]," Chain Agnostic Namespaces, eip155-caip10, December 2019 / March 2022. [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/eip155-caip10.md