Essentially, a wrapped token is a representation of the original token, but it can be used on other blockchains that the original token can’t be used on. A wrapped token is similar to a stablecoin because it derives its value from a different asset that generally lives on the blockchain.
Wrapped tokens allow unsupported assets like ETH to be traded, lent, and borrowed on DeFi platforms like Opensea. Blockchains and their native tokens are unique, meaning that you can’t use Bitcoin on the Ethereum blockchain unless you first wrap the Bitcoin.
Wrapping a token increases the interoperability (the ability to work with other programs) between all the different blockchains and the various DeFi platforms, so that a token can easily be transferred and used on a non-native platform.
One of the most common forms of wrapped tokens you might be familiar with is wrapped ETH (WETH). WETH refers to a ERC-20 compatible form of ether.
ERC-20 is a standard that was developed after the release of ETH that defines how tokens are transferred and how to keep a consistent record of those transfers among tokens on the Ethereum blockchain.
In general, wrapped tokens require a custodian — some type of entity that is responsible for holding an equal amount of the original asset as the wrapped amount. This custodian is generally a merchant, multisig wallet, a DAO, or a smart contract.
In the case of WETH, the custodian needs to hold 1 ETH for each 1 WETH that is minted. Of course, since this is all done on the blockchain (a public ledger), anyone can easily verify this to be true.
Technically speaking, a merchant sends ETH to the custodian to mint the WETH according to the same amount of ETH that’s sent. If the WETH needs to be exchanged back to ETH, the merchant simply sends a burn request to the custodian (this essentially destroys the wrapped version), and the ETH is then released from the reserve to the merchant.
Simply put, the custodian is responsible for wrapping and unwrapping tokens.