Interfaces

OpenZeppelin Contracts for Cairo defines its public interfaces in the dedicated openzeppelin_interfaces package. Applications can use this package independently of the component implementations.

Focused dependencies

A project that only needs to interact with an ERC20 contract can depend on the interfaces package without pulling in the component implementation.

[dependencies]
openzeppelin_interfaces = "2.2.0"

Stable Versioning

The interfaces package follows its own versioning scheme, independent from the implementation packages. Since interfaces are meant to be stable and rarely change, the major version of the interfaces package won’t be updated as frequently as the implementation packages.

This stability means that:

• Dependencies can remain compatible for longer periods
• Breaking changes in implementations won’t force interface updates
• Projects depending only on interfaces are less likely to face version conflicts

Token extension interfaces

The package includes interfaces for the token extensions available in Contracts for Cairo 4.x:

• IERC3156FlashLender and IERC3156FlashBorrower for ERC-3156 flash loans
• IERC6909, IERC6909Metadata, IERC6909TokenSupply, and IERC6909ContentUri for ERC-6909 multi-token contracts
• IERC6909MetadataAdmin and IERC6909ContentUriAdmin for controlled ERC-6909 metadata updates
• IERC20Wrapper and IERC721Wrapper for token wrappers
• IERC1155Supply for ERC1155 supply queries

They can be imported independently of the implementations:

use openzeppelin_interfaces::erc3156::{IERC3156FlashBorrower, IERC3156FlashLender};
use openzeppelin_interfaces::erc6909::{IERC6909, IERC6909Metadata};
use openzeppelin_interfaces::erc20::IERC20Wrapper;
use openzeppelin_interfaces::erc721::IERC721Wrapper;
use openzeppelin_interfaces::erc1155::IERC1155Supply;

Usage

The interfaces package provides three main types of traits that can be imported directly from their respective modules:

Interface Traits

Standard interface traits that define the contract’s functions:

use openzeppelin_interfaces::erc20::IERC20;
use openzeppelin_interfaces::erc721::IERC721;

Dispatchers

Contract dispatchers for interacting with deployed contracts:

use openzeppelin_interfaces::erc20::IERC20Dispatcher;
use openzeppelin_interfaces::erc721::IERC721Dispatcher;

ABI Traits

Complete external ABI definition of a given component/contract:

use openzeppelin_interfaces::erc20::ERC20ABI;
use openzeppelin_interfaces::erc721::ERC721ABI;

This modular approach provides a cleaner and more maintainable way to work with OpenZeppelin contracts, especially in larger projects with multiple dependencies.