ERC-777 Token Standard

Overview

ERC-777 adds richer fungible-token interactions through send and receive hooks discovered through the ERC-1820 registry. Authorized operators can move tokens on behalf of holders, and transactions can carry data for application logic.

Hooks let contracts react to incoming or outgoing tokens and can prevent accidental transfers to unsupported recipients. They also create reentrancy and integration complexity, especially when older applications assume ERC-20 transfers do not execute recipient code. Developers should authenticate operators, secure hooks, understand default operators, and apply checks-effects-interactions or reentrancy protection. Wallets must show operator authorizations clearly. Payment processors should validate actual contract behavior and execution receipts rather than assuming ERC-20 compatibility makes every ERC-777 transfer operationally identical.

Teams adopting ERC-777 should track errata, compatibility changes, and the deployed software versions that enforce it. When evaluating ERC-777, a published standard does not prove universal adoption, safe implementation, or activation on a particular blockchain or payment network. Operational records for ERC-777 should retain the version and configuration used for each relevant transaction or message. When evaluating ERC-777, this allows reproducible debugging when a later upgrade changes parsing, validation, signing, or interoperability behavior.

ERC-777 should be implemented against an exact document revision, status, and activation context. When evaluating ERC-777, draft, final, optional, and network-activated specifications have different authority, and similarly named deployments may support different subsets or extensions. Conformance to ERC-777 requires more than matching a field name or example. When evaluating ERC-777, implementations should validate normative requirements, encodings, error behavior, security conditions, and test vectors, including malformed and boundary inputs that ordinary happy-path tests miss.