EIPs

EIP-55 — Mixed-case address checksum

eips.ethereum.org/EIPS/eip-55

0xd8da6bf26964af9d7eed9e03e53415d37aa96045 is the same address as 0xD8dA6BF26964aF9D7eED9e03E53415D37aA96045 — but only the second one is checksummed. EIP-55 specifies how the case of each hex character encodes a four-bit checksum.

import { to_checksum_address } from "@ethernauta/eip/55";

to_checksum_address("0xd8da6bf26964af9d7eed9e03e53415d37aa96045");
// → "0xD8dA6BF26964aF9D7eED9e03E53415D37aA96045"

Surface

ExportTypePurpose
to_checksum_address(address: string) => AddressNormalize to EIP-55 mixed-case.

When you need it

  • Displaying an address in a UI — checksummed addresses are visually distinguishable.
  • Comparing against a user-pasted string — normalize both sides first.
  • Producing addresses for tooling that expects checksumming (some block explorers reject lowercase).

addressSchema in @ethernauta/core accepts both forms but the canonical output is checksummed.

See also