ERC223

ERC223 is a proposed Ethereum token standard intended to improve upon ERC20 by making token transfers to smart contracts safer and more efficient. Its core goal is to prevent tokens from being accidentally lost when sent to contracts that cannot handle them, a problem occasionally observed with ERC20 transfers.

The standard introduces a transfer mechanism that can include a data payload and a recipient hook. When a transfer is made, the contract checks whether the recipient is a contract. If it is, the transfer triggers a call to the recipient’s tokenFallback function, passing information about the sender, the value, and any data. If the recipient contract does not implement tokenFallback, or if the call fails, the transfer reverts. Transfers to externally owned accounts (regular user wallets) proceed without invoking tokenFallback. This design aims to ensure that contracts explicitly prepared to receive ERC223 tokens can handle them, reducing the risk of token loss.

ERC223 defines two transfer forms: transfer(address to, uint value) and transfer(address to, uint value, bytes data). The latter allows sending additional context or instructions to the recipient contract via the data parameter.

Adoption and status: ERC223 has not achieved the same level of uptake as ERC20. Many projects and wallets continued to rely on ERC20, and other standards such as ERC677 and ERC827 emerged with different approaches to token transfer and contract interaction. Critics of ERC223 point to compatibility concerns and questions about interoperability with existing tooling, contracts, and exchanges. Nevertheless, ERC223 remains part of the broader historical discussion of improving token transfer safety on Ethereum.