OpenSea – Buy and Sell NFTs

# Moralis OpenSea Plugin

This plugin enables interaction with OpenSea.

## Supported chains

This plugins works with 2 different blockchains:

– Ethereum Mainnet (‘mainnet’)
– Ethereum Rinkeby (‘testnet’)

## Supported tokens

– ERC721
– ERC1155

# Utils

Useful endpoints in this plugin:

## Get asset

“`js
const asset = await Moralis.Plugins.opensea.getAsset({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
tokenId: ‘0’,
});
console.log(asset);
“`

## Get orders

“`js
const orders = await Moralis.Plugins.opensea.getOrders({
network: network,
tokenAddress: tokenAddress,
tokenId: tokenId,
orderSide: side,
page: 1, // pagination shows 25 order each page
});
console.log(orders);
“`

# Sellers

Sell an item on OpenSea involves these requirements:

– The `seller` needs to have a proxy contract deployed
– The `seller` has to approve the proxy contract

## Verify seller approvals

“`js
const { proxyContract, approveForAll } = await Moralis.Plugins.opensea.checkSellerApprovals({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
});
“`

`proxyContract` and `approveForAll` are two booleans.
They should both be `true` in order to post a new sell order, however if both or one of them is `false`, you can proceed as follow.

## Deploy a proxy contract

If `checkSellerApprovals()` returns `”proxyContract”: false` the users has to deploy a proxy.
This is a one-time operation in order to be able to sell on OpenSea.

“`js
await Moralis.Plugins.opensea.deployProxy({
network: ‘testnet’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
});
“`

The Moralis SDK will trigger a transaction that deploys the proxy contract.

## Approve ERC721 / 1155

If `checkSellerApprovals()` returns `”approveForAll”: false` the user has to approve his proxy contract to spend ERC 721 / 1155 tokens.

“`js
await Moralis.Plugins.opensea.approveForAll({
network: ‘testnet’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
});
“`

## Create a sell order

Once the seller approvals have been granted, the user can place a new sell order.
Create a new sell order requires two steps:

– Sign the order
– Post the order

### Sign the order

You can sign a sell order as follow:

“`js
const result = await Moralis.Plugins.opensea.signSellOrder({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
tokenId: ‘0’,
tokenType: ‘ERC1155’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
asset: {
tokenId: ‘0’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
schemaName: ‘ERC1155’,
},
startAmount: 1,
endAmount: 0.5, // set it equal to `startAmount` to fix price (not declining)
expirationTime: 10000000000, // do not set if [not declining]
// paymentTokenAddress:, //set if you want to use another erc !== WETH
});
“`

Once the sell order has been signed by the user web3 provider (such as MetaMask) the `result` will contain useful data, necessary to post the sell order.

### Post the order

You can post a sell order as follow:

“`js
await Moralis.Plugins.opensea.postOrder({
message: result.payload.data.hash,
signature: result.response,
orderSide: 1, // Sell
});
“`

The approvals and sell order creation can be merged in one function, to offer the best user experience

“`js
async function signSellOrder() {
// Verify seller approvals
const { proxyContract, approveForAll } = await Moralis.Plugins.opensea.checkSellerApprovals({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
});

if (!proxyContract) {
await Moralis.Plugins.opensea.deployProxy({
network: ‘testnet’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
});
}
if (!approveForAll) {
await Moralis.Plugins.opensea.approveForAll({
network: ‘testnet’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
});
}

const result = await Moralis.Plugins.opensea.signSellOrder({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
tokenId: ‘0’,
tokenType: ‘ERC1155’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
asset: {
tokenId: ‘0’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
schemaName: ‘ERC1155’,
},
startAmount: 1,
endAmount: 0.5, // set to equal to startAmount to fix price (not declining)
expirationTime: 10000000000, // do not set if [not declining]
// paymentTokenAddress: //set if you want to use another erc !== WETH
});

const isPosted = await Moralis.Plugins.opensea.postOrder({
message: result.payload.data.hash,
signature: result.response,
orderSide: 1,
});
if (isPosted) alert(‘The sell order has been posted!’);
}
“`

## Create a buy order

Create a new buy order requires two steps:

– Sign the order
– Post the order

It also requires the `buyer` to approve ERC20 Opensea so that it can take ERC20 tokens from the `buyer`.
If this is necessary, the Moralis SDK will automatically trigger an `approve` transaction when the `buyer` tries to place a buy order.

### Sign the order

You can sign a buy order as follow:

“`js
const result = await Moralis.Plugins.opensea.signBuyOrder({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
tokenId: ‘0’,
amount: 1,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
tokenType: ‘ERC1155’,
});
“`

Once the buy order has been signed by the user web3 provider (such as MetaMask) the `result` will contain useful data, necessary to post the sell order.

### Post the order

You can post a buy order as follow:

“`js
await Moralis.Plugins.opensea.postOrder({
message: result.payload.sign.data.hash,
signature: result.response,
orderSide: 0,
});
“`

The buy order sign and post can be merged in one function, to offer the best user experience

“`js
async function signBuyOrder() {
const result = await Moralis.Plugins.opensea.signBuyOrder({
network: ‘testnet’,
tokenAddress: ‘0xdbe8143c3996c87ecd639ebba5d13b84f56855c2’,
tokenId: ‘0’,
amount: 1,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’,
tokenType: ‘ERC1155’,
});
const isPosted = await Moralis.Plugins.opensea.postOrder({
message: result.payload.sign.data.hash,
signature: result.response,
orderSide: 0,
});
if (isPosted) alert(‘The buy order has been posted!’);
}
“`

### Fulfill a buy order

A `seller` can fulfill any open buy order.
Orders on a single asset can be retrieved by using `getOrders()`.

“`js
await Moralis.Plugins.opensea.fulfillOrder({
network: ‘testnet’,
userAddress: ‘0x730fe9Fa053BB19841D1C2410f5f871F39c8C475’, //seller in this case
order: Order,
});
“`