ERC-7656 (Generalized Token-Linked Services)

ERC-7656, titled Generalized Token-Linked Services and marked Final, was created by Francesco Sullo in March 2024. Its purpose is to generalize the token-bound account idea. Where ERC-6551 links smart accounts to an NFT, ERC-7656 lets you link any kind of contract or service to an NFT or even to another contract, not only accounts.

Technically, it defines a factory, IERC7656Factory, with a create() function for deterministic deployment that takes the implementation, a salt, the chainId, the linking mode, the target contract and, optionally, a tokenId. A bytes12 mode parameter selects how the link is interpreted, supporting LINKED_ID (token-based NFTs and contracts) and NO_LINKED_ID (account contracts). Deployment uses ERC-1167 minimal proxies with immutable bytecode encoding the parameters, which guarantees predictable addresses and a stateless factory.

The relationship with ERC-6551 is conceptual and design-level: the official text does not cite that standard by number, though it does acknowledge prior token-bound account projects as motivation, noting they were restricted to NFTs. The author documented this generalization on Ethereum Magicians in March 2024. It matters because it extends an NFT's utility by attaching services such as vesting, vaults, plugins or data modules without touching existing infrastructure. The most direct ecosystem is the author's own, tied to the Cruna project.