Understanding and Developing an ERC-5725 Contract
Ethereum Improvement Proposal 5725: Transferable Vesting NFTs is an EIP created to offer a standardized Non-Fungible Token (NFT) API to enable vesting ERC-20 tokens over a vesting release curve. Read on to learn more about how to implement EIP-5725 for your own use cases, and feel free to reach out to ApeTastic, coauthor of the EIP, on Telegram at @Ape_tastic with any questions.
Following the Specification
After reading through EIP-5725, the main section you will focus on during integration will be the EIP-5725 specification.
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.
During the integration process, take some time to read carefully through the natspec comments of the EIP-5725 specification to ensure you are implementing the functions the correct way. The key words above help define how the functions should work, given different inputs.
IERC5725.sol on GitHub
A usable IERC5725.sol is stored publicly on the GitHub ERC-5725 reference implementation. This can be used as the base for ERC-5725 NFTs.
Follow along below for how to use this interface to create your own ERC-5725 NFTs.
Implementing an ERC-5725 Contract
Obtain the Base Contracts
The simplest way to get started is to head to the EIP-5725 Reference Implementation GitHub repository and click the button Use this template to quickly create a copy of the code under your own GitHub profile.
Click “Use this template” to copy the reference code
Otherwise, you can use git clone to copy the code locally, or even download the code in .ZIP files under the <> Code drop down.
$ git clone git@github.com:ApeSwapFinance/eip-5725-vesting-nft-implementation.git$ cd eip-5725-vesting-nft-implementation
Use git clone to pull the reference code
Extending ERC5725.sol: Easily Create Vesting NFTs
ERC5725.sol is a valid IERC-5725 implementation which can be used as a base to quickly create Vesting NFTs.
// To Write
ERC5725.sol is an abstract contract. To be able to implement ERC5725.sol you will need to import it into a parent contract and override 5 virtual functions:
- vestedPayoutAtTime: Total amount of vested tokens at the provided timestamp for a given tokenId. This number also includes vested tokens which have been claimed.
- _payoutToken: Payout token of a given tokenId.
- _payout: The total payout of a given tokenId.
- _startTime: The unix timestamp of when vesting starts for a given tokenId.
- _endTime: The unix timestamp of when vesting ends for a given tokenId.
Full ERC5725 Implementation// To Write
Two contracts are fully implemented in the reference directory: LinearVestingNFT and VestingNFT.
Example LinearVestingNFT
- Extend ERC5725 by importing it: contract LinearVestingNFT is ERC5725
- It can be seen in this implementation that the five virtual functions above are implemented in this contact with override specifiers
- vestedPayoutAtTime is the central place to be able to change the vesting curve. In this case, it first checks that the _cliff has passed, otherwise it will linearly release tokens between the _startTime and _endTime
Implement Your Own!// To Write
- ERC5725.sol is a great starting place to easily get off the ground with Vesting NFTs.
- Use the reference implementations shared above as a guide to easily implement your own!
Resources