How to do gasless tx with the ncw wallets

Developer Discussion
1

hey , so i have some calls to make from ncw wallets like erc20 token approvals and all and for that i need to do gasless tx , how to do that from the users ncw wallet ?

And if theres a gas relayer concept is there a doc for this , cause i cant find on how to do that

2

I tried doing relay transaction using gelato but can you provide some documentation on how to do that
This is a example doc in gelato to do the tx -

const counter = "0x00172f67db60E5fA346e599cdE675f0ca213b47b"; 
const abi = ["function increment()"];
const provider = new ethers.BrowserProvider(window.ethereum);
const signer = await provider.getSigner();
const user = await signer.getAddress();

// Generate the target payload
const contract = new ethers.Contract(counter, abi, signer);
const { data } = await contract.incrementContext.populateTransaction();

// Populate a relay request
const request: CallWithERC2771Request = {
  chainId: (await provider.getNetwork()).chainId,
  target: counter;
  data: data;
  user: user;
};

// Without a specific API key, the relay request will fail! 
// Go to https://relay.gelato.network to get a testnet API key with 1Balance.
// Send a relay request using Gelato Relay!
const relayResponse = await relay.sponsoredCallERC2771(request, provider, apiKey);

but is there any example implementation on how to do this with users ncw on fireblock sdk as i cant fund any direct way in fireblocks to relay this tx instead of gelato … so can you give a example code on how to do gasless tx using ncw fireblock and fireblocks tx endpoint

3

Also the only way to do sign in fireblocks sdk is by signing the tx id of a fireblocks tx … so i need to first create cbdc approval tx then i sign that tx with fireblocks sdk using the tx id and then how do i relay that signed tx through gelator or some other service , can you please clarify the flow for this

4

Hi @tan so gasless only works with a Fireblocks relay. We will have more documentation in the dev portal coming soon in H1 2025.