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Integrate Fee Delegation Features into Wallets
Thanks to Kaia’s native fee delegation feature, users can enjoy gas-less transactions on dApps. However, to enable this functionality, wallets must support fee-delegated transaction types. This guide explains how wallet providers can integrate fee delegation capabilities into their wallets.
To integrate fee delegation, wallet providers should:
- Add the Kaia SDK (for example, kaiachain/ethers-ext) to your codebase.
- Whenever the RPC method of the wallet provider,
kaia_signTransaction
, is called, use the Kaia SDK to sign the transaction. - As a result, the wallet should return the signed transaction,
senderTxHashRlp
, to the dApp instead of sending it directly to the node provider. It will be transferred to the fee payer.
Below is a basic example for a simple value transfer:
const ethers = require("ethers6"); const { Wallet, TxType, parseKaia } = require("@kaiachain/ethers-ext/v6"); const senderAddr = "0xa2a8854b1802d8cd5de631e690817c253d6a9153"; const senderPriv = "0x0e4ca6d38096ad99324de0dde108587e5d7c600165ae4cd6c2462c597458c2b8"; const recieverAddr = "0xc40b6909eb7085590e1c26cb3becc25368e249e9"; const provider = new ethers.JsonRpcProvider( "https://public-en-kairos.node.kaia.io" ); const senderWallet = new Wallet(senderPriv, provider); async function main() { const tx = {type: TxType.FeeDelegatedValueTransfer, from: senderAddr, to: recieverAddr, value: parseKaia("0.01"), }; // Sign transaction by senderconst populatedTx = await senderWallet.populateTransaction(tx); const senderTxHashRLP = await senderWallet.signTransaction(populatedTx); console.log("senderTxHashRLP", senderTxHashRLP); }
For contract interactions:
const ethers = require("ethers6"); const { Wallet, TxType, parseKaia } = require("@kaiachain/ethers-ext/v6"); const senderAddr = "0xa2a8854b1802d8cd5de631e690817c253d6a9153"; const senderPriv = "0x0e4ca6d38096ad99324de0dde108587e5d7c600165ae4cd6c2462c597458c2b8"; const provider = new ethers.JsonRpcProvider( "https://public-en-kairos.node.kaia.io" ); const senderWallet = new Wallet(senderPriv, provider); const contractAddr = "0x95Be48607498109030592C08aDC9577c7C2dD505";const abi = ["function setNumber(uint256 newNumber)"];async function main() { const contract = new ethers.Contract(contractAddr, abi, provider);const data = contract.interface.encodeFunctionData("setNumber", ["0x123"]);const tx = {type: TxType.FeeDelegatedSmartContractExecution, from: senderAddr,to: recieverAddr, value: 0, data: data,}; // Sign transaction by senderconst populatedTx = await senderWallet.populateTransaction(tx); const senderTxHashRLP = await senderWallet.signTransaction(populatedTx); console.log("senderTxHashRLP", senderTxHashRLP); }
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The exact integration code may vary depending on your wallet’s implementation.