Smart Contract Deployment on Kaia: A Developer’s Guide

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Deploying smart contracts is a foundational skill for blockchain developers. On the Kaia network, this process leverages a unique transaction type known as TxTypeSmartContractDeploy, enabling secure and efficient deployment of decentralized applications (dApps). This guide walks you through the end-to-end workflow of deploying a smart contract using Kaia's infrastructure, with practical code examples and best practices.

Whether you're building DeFi protocols, NFT marketplaces, or enterprise-grade dApps, understanding how to deploy contracts on Kaia opens doors to high-performance, low-latency blockchain solutions.

Understanding Smart Contract Deployment on Kaia

Kaia supports fee-delegated transactions, allowing one party (the sender) to initiate a contract deployment while another (the fee payer) covers gas costs. This separation enhances usability in enterprise and user-facing applications where gas abstraction is essential.

The core transaction type used here is FeeDelegatedSmartContractDeploy, which requires two signatures:

This model improves scalability and user experience, especially in wallet-as-a-service or custodial environments.

👉 Discover how blockchain developers are streamlining smart contract workflows today.

Setting Up Your Development Environment

To begin, ensure you have Node.js installed and set up your project with the required dependencies:

npm install web3 @kaiachain/web3js-ext

The @kaiachain/web3js-ext package extends standard Web3 functionality with Kaia-specific transaction types and signing methods, making it essential for interacting with the Kaia blockchain.

Once installed, import the necessary modules:

const { Web3, TxType } = require("@kaiachain/web3js-ext");

Next, configure your provider to connect to the Kaia testnet (kairos) or a third-party node service like QuickNode:

const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");
const web3 = new Web3(provider);

Using reliable node providers ensures consistent access to blockchain data and reduces latency during development and deployment.

Configuring Accounts and Keys

Secure account management is crucial. Define your sender and fee payer addresses along with their private keys:

const senderAddr = "0xa2a8854b1802d8cd5de631e690817c253d6a9153";
const senderPriv = "0x0e4ca6d38096ad99324de0dde108587e5d7c600165ae4cd6c2462c597458c2b8";

const feePayerAddr = "0xcb0eb737dfda52756495a5e08a9b37aab3b271da";
const feePayerPriv = "0x9435261ed483b6efa3886d6ad9f64c12078a0e28d8d80715c773e16fc000cff4";

Then, create wallet instances from the private keys:

const senderAccount = web3.eth.accounts.privateKeyToAccount(senderPriv);
const feePayerAccount = web3.eth.accounts.privateKeyToAccount(feePayerPriv);

These accounts will be used to sign the transaction at different stages.

Building the Deployment Transaction

Construct the transaction object with all required parameters:

const tx = {
  type: TxType.FeeDelegatedSmartContractDeploy,
  from: senderAddr,
  data: "0x608060405234801561001057600080fd5b5060f78061001f6000396000f3fe...",
  humanReadable: false,
  codeFormat: 0,
};

Key fields explained:

This structure ensures compatibility with Kaia’s consensus rules and execution environment.

Signing and Submitting the Transaction

Deployment involves two signing steps:

  1. The sender signs the transaction:
const signResult1 = await senderAccount.signTransaction(tx);
console.log("senderTxHashRLP", signResult1.rawTransaction);
  1. The fee payer then signs as the transaction submitter:
const signResult2 = await feePayerAccount.signTransactionAsFeePayer(signResult1.rawTransaction);
console.log("signedTx", signResult2.transactionHash);

Finally, broadcast the fully signed transaction to the network:

const receipt = await web3.eth.sendSignedTransaction(signResult2.rawTransaction);
console.log("receipt", receipt);

A successful deployment returns a transaction receipt containing:

👉 Learn how leading developers optimize blockchain deployment pipelines.

Interpreting the Deployment Output

After running the script with node FeeDelegatedSmartContractDeployExample.js, you’ll see output similar to:

senderTxHashRLP 0x29f90188...
signedTx 0x57cf3bfddf3e72effc39e80b9cb6995273822e51d50f55da93a14574b5dae9d1
receipt {
  blockHash: '0x84f6aefd...',
  blockNumber: 148744885n,
  contractAddress: '0x661c557c1b7c2b1fbd6c4793d210cd1e421064e9',
  status: 1n,
  transactionHash: '0x57cf3bfddf3e72effc39e80b9cb6995273822e51d50f55da93a14574b5dae9d1'
}

The presence of a valid contractAddress confirms successful deployment. You can now interact with your contract using its address and ABI.

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Frequently Asked Questions

What is FeeDelegatedSmartContractDeploy?

It’s a transaction type on Kaia that allows one party (sender) to deploy a contract while another (fee payer) covers gas fees. This enables gasless user experiences in dApps.

Why must humanReadable be false?

Smart contract deployments require machine-readable bytecode. Setting humanReadable: true would interfere with EVM execution and cause deployment failure.

Can I use QuickNode instead of Kaia’s public endpoint?

Yes. Replace the provider URL with your QuickNode endpoint for enhanced performance, reliability, and API limits.

How do I get the contract’s bytecode?

Compile your Solidity code using tools like Hardhat, Remix, or Foundry. The output includes bytecode under the artifact JSON file.

What happens if the fee payer doesn’t sign?

The transaction remains unsigned and cannot be broadcast. Both signatures are mandatory for validation on Kaia’s network.

Is this method compatible with other EVM chains?

While the signing logic is Kaia-specific due to extended Web3 methods, the underlying principles apply across EVM-compatible networks with minor adjustments.

👉 Explore tools that simplify multi-chain smart contract deployment.

Final Thoughts

Deploying smart contracts on Kaia combines Ethereum familiarity with enhanced scalability through fee delegation. By mastering FeeDelegatedSmartContractDeploy, developers can build more flexible and user-friendly dApps, particularly in scenarios requiring gas abstraction or institutional-grade control over transaction costs.

With proper tooling, secure key management, and a clear understanding of Kaia’s extended Web3 interface, you’re well-equipped to launch innovative blockchain applications efficiently.