Creating a NFT trade order where the maker is selling a single 721 NFT, and the taker (same address as maker) is offering to buy it for eth. No matter what I set the expiry value to, the transactions fails when estimating gas. I can only get it to work when expiry is set to the default value of never expire-- 2524604400

Here's a working example, minimally adapted from the nft trader sdk example---

export const nftSwapTestExample = async (
  provider: BaseProvider,
  signer: Signer,
  accountAddress: string,
  expiresInSeconds: number,
) => {
  // Scenario: User A wants to sell their CryptoPunk for 420 WETH
  const chainId = await signer.getChainId();
  // Set up the assets we want to swap (CryptoPunk #69 and 420 WETH)
  const CRYPTOPUNK: SwappableAssetV4 = {
    tokenAddress: '0xc3415e01ecd8021e1608fda6c7f7a75af0ed5be0',
    tokenId: '0',
    type: 'ERC721', // 'ERC721' or 'ERC1155'

  const FOUR_HUNDRED_TWENTY_WETH: SwappableAssetV4 = {
    tokenAddress: '0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee', // ETH contract address
    amount: ethers.utils.parseEther('0.0001').toString(),
    type: 'ERC20',

  // [Part 1: Maker (owner of the Punk) creates trade]
  const nftSwapSdk = new NftSwapV4(provider, signer, chainId);
  const walletAddressMaker = accountAddress;

  // Approve NFT to trade (if required)
  const needsApproval = await nftSwapSdk.loadApprovalStatus(CRYPTOPUNK, walletAddressMaker);
  if (!needsApproval.contractApproved && !needsApproval.tokenIdApproved) {
    await nftSwapSdk.approveTokenOrNftByAsset(CRYPTOPUNK, walletAddressMaker);

  const expiry = Math.floor(Date.now() / 1000 + expiresInSeconds);

  // Build order
  const order = nftSwapSdk.buildOrder(
    CRYPTOPUNK, // Maker asset to swap
    FOUR_HUNDRED_TWENTY_WETH, // Taker asset to swap
    { expiry },
  // Sign order so order is now fillable
  const signedOrder = await nftSwapSdk.signOrder(order);

  // [Part 2: Taker that wants to buy the punk fills trade]

  // Fill order :)
  const fillTx = await nftSwapSdk.fillSignedOrder(signedOrder);
  const fillTxReceipt = await nftSwapSdk.awaitTransactionHash(fillTx.hash);
  console.log(`🎉 🥳 Order filled. TxHash: ${fillTxReceipt.transactionHash}`);

// expires in 1 hour, fails
await nftSwapTestExample(provider, signer, 'address', 60*60);
// expires in 1 day, fails
await nftSwapTestExample(provider, signer, 'address', 60*60*24);

1 Answer 1


Thanks for the report. I fixed the buildOrder function to correctly support passing a raw unix timestamp for expiry. Please update to v0.21 when you get a chance!

Now expiry properly supports either a Date object or a unix timestamp (as a number type).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.