You can transfer NFTs with Rarible Multichain Protocol in different blockchains.

Before start, install and configure Rarible SDK and required wallets.

To get balance of your wallet, use getBalance function:

import { createRaribleSdk } from "@rarible/sdk"
import { toUnionAddress } from "@rarible/types"
import type { BlockchainWallet } from "@rarible/sdk-wallet/src"
import type { AssetType } from "@rarible/api-client"

async function getBalance(wallet: BlockchainWallet, assetType: AssetType) {
	const sdk = createRaribleSdk(wallet, "dev")
	const balance = await sdk.balances.getBalance(
		toUnionAddress("<YOUR_WALLET_ADDRESS>"),
		assetType
	)
	return balance
}

For getting balance from Polygon:

Matic

const balance = await sdk.balances.getBalance(
  toUnionAddress("ETHEREUM:0xc8f35463Ea36aEE234fe7EFB86373A78BF37e2A1"), {
 "@type": "ETH",
 blockchain: Blockchain.POLYGON,
})

ERC20

const balance = await sdk.balances.getBalance(
toUnionAddress("ETHEREUM:0xc8f35463Ea36aEE234fe7EFB86373A78BF37e2A1"), {
			"@type": "ERC20",
			contract: toCollectionId("POLYGON:0xa6fa4fb5f76172d178d61b04b0ecd319c5d1c0aa"),
})