NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/gsn
This set of contracts provide all the tools required to make a contract callable via the https://gsn.openzeppelin.com[Gas Station Network].
This set of contracts provide all the tools required to make a contract callable via the https://gsn.openzeppelin.com[Gas Station Network].
TIP: If you're new to the GSN, head over to our xref:learn::sending-gasless-transactions.adoc[overview of the system] and basic guide to xref:ROOT:gsn.adoc[creating a GSN-capable contract].
TIP: If you're new to the GSN, head over to our xref:learn::sending-gasless-transactions.adoc[overview of the system] and basic guide to xref:ROOT:gsn.adoc[creating a GSN-capable contract].
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/introspection
This set of interfaces and contracts deal with https://en.wikipedia.org/wiki/Type_introspection[type introspection] of contracts, that is, examining which functions can be called on them. This is usually referred to as a contract's _interface_.
This set of interfaces and contracts deal with https://en.wikipedia.org/wiki/Type_introspection[type introspection] of contracts, that is, examining which functions can be called on them. This is usually referred to as a contract's _interface_.
Ethereum contracts have no native concept of an interface, so applications must usually simply trust they are not making an incorrect call. For trusted setups this is a non-issue, but often unknown and untrusted third-party addresses need to be interacted with. There may even not be any direct calls to them! (e.g. `ERC20` tokens may be sent to a contract that lacks a way to transfer them out of it, locking them forever). In these cases, a contract _declaring_ its interface can be very helpful in preventing errors.
Ethereum contracts have no native concept of an interface, so applications must usually simply trust they are not making an incorrect call. For trusted setups this is a non-issue, but often unknown and untrusted third-party addresses need to be interacted with. There may even not be any direct calls to them! (e.g. `ERC20` tokens may be sent to a contract that lacks a way to transfer them out of it, locking them forever). In these cases, a contract _declaring_ its interface can be very helpful in preventing errors.
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/payment
Utilities related to sending and receiving payments. Examples are {PullPayment}, which implements the best security practices when sending funds to third parties, and {PaymentSplitter} to receive incoming payments among a number of beneficiaries.
Utilities related to sending and receiving payments. Examples are {PullPayment}, which implements the best security practices when sending funds to third parties, and {PaymentSplitter} to receive incoming payments among a number of beneficiaries.
TIP: When transferring funds to and from untrusted third parties, there is always a security risk of reentrancy. If you would like to learn more about this and ways to protect against it, check out our blog post https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
TIP: When transferring funds to and from untrusted third parties, there is always a security risk of reentrancy. If you would like to learn more about this and ways to protect against it, check out our blog post https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/presets
These contracts integrate different Ethereum standards (ERCs) with custom extensions and modules, showcasing common configurations that are ready to deploy **without having to write any Solidity code**.
These contracts integrate different Ethereum standards (ERCs) with custom extensions and modules, showcasing common configurations that are ready to deploy **without having to write any Solidity code**.
They can be used as-is for quick prototyping and testing, but are **also suitable for production environments**.
They can be used as-is for quick prototyping and testing, but are **also suitable for production environments**.
NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/utils
Miscellaneous contracts and libraries containing utility functions you can use to improve security, work with new data types, or safely use low-level primitives.
Miscellaneous contracts and libraries containing utility functions you can use to improve security, work with new data types, or safely use low-level primitives.
