= ERC 20
[.readme-notice] NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/token/erc20
This set of interfaces, contracts, and utilities are all related to the https://eips.ethereum.org/EIPS/eip-20[ERC20 Token Standard].
TIP: For an overview of ERC20 tokens and a walk through on how to create a token contract read our xref:ROOT:erc20.adoc[ERC20 guide].
There a few core contracts that implement the behavior specified in the EIP:
- {IERC20}: the interface all ERC20 implementations should conform to.
- {IERC20Metadata}: the extended ERC20 interface including the <<ERC20-name,
name
>>, <<ERC20-symbol,symbol
>> and <<ERC20-decimals,decimals
>> functions. - {ERC20}: the implementation of the ERC20 interface, including the <<ERC20-name,
name
>>, <<ERC20-symbol,symbol
>> and <<ERC20-decimals,decimals
>> optional standard extension to the base interface.
Additionally there are multiple custom extensions, including:
- {ERC20Burnable}: destruction of own tokens.
- {ERC20Capped}: enforcement of a cap to the total supply when minting tokens.
- {ERC20Pausable}: ability to pause token transfers.
- {ERC20Snapshot}: efficient storage of past token balances to be later queried at any point in time.
- {ERC20Permit}: gasless approval of tokens (standardized as ERC2612).
- {ERC20FlashMint}: token level support for flash loans through the minting and burning of ephemeral tokens (standardized as ERC3156).
- {ERC20Votes}: support for voting and vote delegation.
- {ERC20VotesComp}: support for voting and vote delegation (compatible with Compound's token, with uint96 restrictions).
- {ERC20Wrapper}: wrapper to create an ERC20 backed by another ERC20, with deposit and withdraw methods. Useful in conjunction with {ERC20Votes}.
Finally, there are some utilities to interact with ERC20 contracts in various ways.
- {SafeERC20}: a wrapper around the interface that eliminates the need to handle boolean return values.
- {TokenTimelock}: hold tokens for a beneficiary until a specified time.
The following related EIPs are in draft status.
- {ERC20Permit}
NOTE: This core set of contracts is designed to be unopinionated, allowing developers to access the internal functions in ERC20 (such as <<ERC20-_mint-address-uint256-,_mint
>>) and expose them as external functions in the way they prefer. On the other hand, xref:ROOT:erc20.adoc#Presets[ERC20 Presets] (such as {ERC20PresetMinterPauser}) are designed using opinionated patterns to provide developers with ready to use, deployable contracts.
== Core
{{IERC20}}
{{IERC20Metadata}}
{{ERC20}}
== Extensions
{{ERC20Burnable}}
{{ERC20Capped}}
{{ERC20Pausable}}
{{ERC20Snapshot}}
{{ERC20Votes}}
{{ERC20VotesComp}}
{{ERC20Wrapper}}
{{ERC20FlashMint}}
== Draft EIPs
The following EIPs are still in Draft status. Due to their nature as drafts, the details of these contracts may change and we cannot guarantee their xref:ROOT:releases-stability.adoc[stability]. Minor releases of OpenZeppelin Contracts may contain breaking changes for the contracts in this directory, which will be duly announced in the https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/CHANGELOG.md[changelog]. The EIPs included here are used by projects in production and this may make them less likely to change significantly.
{{ERC20Permit}}
== Presets
These contracts are preconfigured combinations of the above features. They can be used through inheritance or as models to copy and paste their source code.
{{ERC20PresetMinterPauser}}
{{ERC20PresetFixedSupply}}
== Utilities
{{SafeERC20}}
{{TokenTimelock}}