The Optimism ERC-721 Bridge is finally here! For many collectors and developers, interacting with bridged NFTs on Optimism won’t be any different than on Ethereum, but for those who interact with NFT metadata frequently or display bridged NFTs on their platforms, there is something to look out for:
New tokenURI Format
Calling the tokenURI function for an NFT that has been bridged to Optimism will return a URL in the EIP-681 format, rather than a typical IPFS or HTTPS link. The bridged metadata link will start with the ethereum prefix, followed by the contract address, chain ID, function, and token ID.
For example, calling tokenURI on a bridged token might return the following: ethereum:[email protected]/tokenURI?tokenId=1. To get the actual token metadata, you should then call the function tokenURI(1) on the contract 0x099689220846644f87d1137665cded7bf3422747, which can be found on Ethereum chain ID 1, commonly referred to as eth-mainnet.
We use this format so that any metadata changes made to the NFT on L1 are always reflected on the bridged NFT as well. We recommend adjusting to account for this standard if your platform runs an indexer and/or wants to display NFTs that have been bridged to Optimism.