### One-Click RPC Node Setup

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Use this script to quickly set up an RPC node with Flashblocks enabled. Ensure Docker and Docker Compose are installed and you have access to a Flashblocks WebSocket endpoint.

```shell
mkdir -p /data/xlayer-mainnet && cd /data/xlayer-mainnet
curl -fsSL https://raw.githubusercontent.com/okx/xlayer-toolkit/main/rpc-setup/one-click-setup.sh -o one-click-setup.sh
chmod +x one-click-setup.sh
./one-click-setup.sh --rpc_type=reth
```

--------------------------------

### Install Go SDK for SHA3

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Install the Go SDK for SHA3 hashing. This is a prerequisite for address formatting.

```bash
go get golang.org/x/crypto/sha3
```

--------------------------------

### Install and Connect to WSS Server

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/websockets-endpoints/websocket-endpoints

Install the 'ws' tool and connect to the XLayer WSS server. This is useful for establishing real-time communication with the network.

```shell
# install wss tools
go install github.com/hashrocket/ws@latest

# connect to the wss server
ws wss://xlayertestws.okx.com
```

--------------------------------

### Install Foundry

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-foundry

Installs Foundry using a curl command. Ensure Node.js and Git are installed beforehand.

```shell
curl -L https://foundry.paradigm.xyz | bash
```

--------------------------------

### Install Hardhat Explorer Verify Plugin

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Install the recommended Hardhat plugin for contract verification on OKLink.

```bash
npm install @okxweb3/hardhat-explorer-verify
```

--------------------------------

### Install Truffle

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-truffle

Install the Truffle development framework globally using npm. This command is typically run once to set up the tool for your system.

```shell
npm install -g truffle
```

--------------------------------

### Fully Automatic X Layer RPC Node Setup

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/setup-rpc/setup-rpc

Deploys a mainnet reth node with snapshot sync and default ports automatically. No user input is required after execution.

```bash
curl -sSf https://raw.githubusercontent.com/okx/xlayer-toolkit/main/rpc-setup/one-click-setup.sh | bash
```

--------------------------------

### Counter Smart Contract Example

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-foundry

A basic Solidity smart contract named 'Counter' with functions to set and increment a number.

```solidity
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}
```

--------------------------------

### Python SDK: Address Conversion and Error Handling

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Shows how to convert between XKO and standard EVM addresses using the Python SDK. Includes examples of successful conversions and error handling for invalid inputs.

```python
from multi_address import to_evm_address, from_evm_address

# XKO to EVM
evm_addr = to_evm_address('XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625')
print(evm_addr)
# Output: 0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625

# EVM to XKO
xko_addr = from_evm_address('0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625')
print(xko_addr)
# Output: XKO70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
```

```python
# Error handling
try:
    to_evm_address('invalid')
except ValueError as e:
    print(e)
    # Output: Invalid address length: expected 40 hex chars, got 7
```

--------------------------------

### Address Equivalence Examples

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Demonstrates the equivalence between standard EVM and XKO addresses, including valid and invalid formats. Case-insensitivity of the XKO prefix is also shown.

```plaintext
Standard EVM:  0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
XKO address:   XKO70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
               xko70586beeb7b7aa2e7966df9c8493c6cbfd75c625  ✓ Valid
               Xko70586beeb7b7aa2e7966df9c8493c6cbfd75c625  ✓ Valid
```

```plaintext
XKO0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625  ✗ Cannot have both XKO and 0x
```

--------------------------------

### Truffle Contract Deployment Output

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-truffle

This is an example of the output you will see after successfully deploying a contract. Note that your specific details like transaction hash and contract address will differ.

```shell
1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0xaf4502198400bde2148eb4274b08d727a17080b685cd2dcd4aee13d8eb954adc
   > Blocks: 3            Seconds: 9
   > contract address:    0x81eCD10b61978D9160428943a0c0Fb31a5460466
   > block number:        3223948
   > block timestamp:     1604049862
   > account:             0x623ac9f6E62A8134bBD5Dc96D9B8b29b4B60e45F
   > balance:             6.24574114
   > gas used:            191943 (0x2edc7)
   > gas price:           20 gwei
   > value sent:          0 ETH
   > total cost:          0.00383886 ETH

   Pausing for 5 confirmations...
   ------------------------------
   > confirmation number: 2 (block: 3223952)
   > confirmation number: 3 (block: 3223953)
   > confirmation number: 4 (block: 3223954)
   > confirmation number: 6 (block: 3223956)

   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:          0.00383886 ETH


Summary
=======
> Total deployments:   1
> Final cost:          0.00383886 ETH

```

--------------------------------

### Get Contract Bytecode with Pending State

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Fetch the contract bytecode deployed at a specific address, querying the pending state with the 'pending' tag.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getCode","params":["0x...","pending"],"id":1}'
```

--------------------------------

### Check Smart Contract Verification Status with Foundry

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-foundry

After verification, use this command to check the status. It requires the chain ID, the OKLink verifier URL, and the verification GUID. The `--watch` flag can be used with `verify-contract` for real-time polling.

```bash
forge verify-check --chain 11155111 --verifier oklink --verifier-url https://www.oklink.com/api/v5/explorer/contract/verify-source-code-plugin/{chainShortName} <GUID>

```

--------------------------------

### Create and Initialize Truffle Project

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-truffle

Create a new directory for your project and then initialize a new Truffle project within that directory. This sets up the standard project structure.

```shell
mkdir MegaCoin
cd MegaCoin
truffle init
```

--------------------------------

### Initialize Foundry Project

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-foundry

Initializes a new Foundry project named 'hello_contract' and navigates into the project directory.

```shell
forge init hello_contract
cd hello_contract
```

--------------------------------

### Get Raw Transaction by Hash

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Fetches the raw, RLP-encoded transaction data for a given transaction hash.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getRawTransactionByHash","params":["0x..."],"id":1}'
```

--------------------------------

### Get Block Transaction Count by Hash

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Returns the number of transactions within a block identified by its hash.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBlockTransactionCountByHash","params":["0x..."],"id":1}'
```

--------------------------------

### Get Block Receipts

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Retrieves transaction receipts for a specified block. Use 'pending' for pending blocks.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBlockReceipts","params":["pending"],"id":1}'
```

--------------------------------

### Initialize Hardhat Project

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-hardhat

Run this command in your project folder to create a new Hardhat project. It prompts you to choose between JavaScript or TypeScript projects, or an empty configuration file.

```shell
npx hardhat
```

--------------------------------

### Get Transaction by Block Hash and Index

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Retrieves transaction details using the block hash and the transaction's index within that block.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getTransactionByBlockHashAndIndex","params":["0x...","0x0"],"id":1}'
```

--------------------------------

### Configure Hardhat with Explorer Verify Plugin

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Configure your `hardhat.config.js` or `hardhat.config.ts` to use the `@okxweb3/hardhat-explorer-verify` plugin. Ensure network details and API keys are correctly set.

```typescript
import {
  HardhatUserConfig,
} from "hardhat/config";
import "@nomicfoundation/hardhat-toolbox";
import '@okxweb3/hardhat-explorer-verify'; // Import the plugin

const config: HardhatUserConfig = {
  solidity: "0.8.20",
  sourcify: {
    enabled: true,
  },
  networks: {
    xlayer: {
      url: "https://xlayerrpc.example.com",
      accounts: ["<Your Wallet Private Key>"],
    },
  },
  etherscan: {
     apiKey: '...'
  },
  okxweb3explorer: {
    apiKey: "<Your API Key>",
  }
};

export default config;
```

--------------------------------

### Get Block Transaction Count by Number

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Returns the total number of transactions for a given block number. Use 'pending' for pending blocks.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBlockTransactionCountByNumber","params":["pending"],"id":1}'
```

--------------------------------

### Go: Convert XKO to EVM and EVM to XKO Addresses

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Use the Go SDK to convert between XKO and EVM address formats. Ensure correct module path for 'your-module/multi_address'.

```go
package main

import (
    "fmt"
    "log"

    address "your-module/multi_address"
)

func main() {
    // XKO to EVM
    evmAddr, err := address.ToEvmAddress("XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(evmAddr)
    // Output: 0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625

    // EVM to XKO
    xkoAddr, err := address.FromEvmAddress("0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(xkoAddr)
    // Output: XKO70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
}
```

--------------------------------

### Get Block by Hash with Flashblocks

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Retrieve a block using its hash. Note that flashblocks and canonical blocks share the same number but may have different hashes.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBlockByHash","params":["0x...",true],"id":1}'
```

--------------------------------

### Download Mainnet Geth Snapshot

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/setup-rpc/snapshots

Use this command to download the latest mainnet snapshot for the Geth client. Ensure you have sufficient disk space and a stable internet connection.

```bash
wget https://static.okx.com/cdn/chain/xlayer/snapshot/$(curl -s https://static.okx.com/cdn/chain/xlayer/snapshot/geth-mainnet-latest)
```

--------------------------------

### Flashblocks Diff Response Example

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

This JSON structure represents an incremental Flashblocks message, containing only transaction diffs. It is used when the index is greater than 0.

```json
{
  "diff": {
    "blob_gas_used": "0x0",
    "block_hash": "0x...",
    "gas_used": "0xbe6b",
    "logs_bloom": "0x...",
    "receipts_root": "0x...",
    "state_root": "0x...",
    "transactions": [],
    "withdrawals": [],
    "withdrawals_root": "0x..."
  },
  "index": 1,
  "metadata": {
    "block_number": 8595627,
    "new_account_balances": {
      "0x0000f90827f1c53a10cb7a02335b175320002935": "0x0"
    },
    "receipts": {
      "0x30130a020af408787a9388dcf0272635fff7bc15ae118edb76d207391bb57b51": {
        "Legacy": {}
      }
    }
  },
  "payload_id": "0x03307607ad2ba79d"
}
```

--------------------------------

### Create Viem Wallet Client with Data Suffix

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/builder-codes/integration

Create a Viem wallet client and configure it with the `dataSuffix` option using your Builder Code. This ensures all transactions sent from this client are automatically attributed.

```typescript
// client.ts
import { createWalletClient, custom } from "viem";
import { Attribution } from "ox/erc8021";
import { xlayer } from "./chain";

const DATA_SUFFIX = Attribution.toDataSuffix({
  codes: ["YOUR-BUILDER-CODE"],
});

if (!window.ethereum) {
  throw new Error("No injected wallet found");
}

export const walletClient = createWalletClient({
  chain: xlayer,
  transport: custom(window.ethereum),
  dataSuffix: DATA_SUFFIX,
});
```

--------------------------------

### Verify Contract using Hardhat Explorer Plugin

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Run this command after deploying your contracts to verify them on the OKX Chain explorer using the Hardhat plugin.

```bash
npx hardhat okverify --network xlayer <Your Contract Address>
```

--------------------------------

### Live Test: eth_getBalance via Flashblocks RPC

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Perform a live test by querying the `eth_getBalance` method on the public X Layer Flashblocks RPC endpoint. Replace the address placeholder with a valid address.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBalance","params":["0x...","pending"],"id":1}'
```

--------------------------------

### Get Storage Value at Position with Pending State

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Retrieve the storage value at a specific position for a given address, querying the pending state using the 'pending' tag.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getStorageAt","params":["0x...","0x0","pending"],"id":1}'
```

--------------------------------

### Send Transaction with Viem on X Layer

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

This snippet demonstrates how to send a transaction using Viem on the X Layer network. It includes setting up the chain configuration, wallet client, and public client, then sending and confirming a transaction.

```javascript
import { createWalletClient, createPublicClient, http, defineChain } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import dotenv from 'dotenv';

dotenv.config();

// TODO: create PR to viem
const xlayerPreconf = defineChain({
    id: 195,
    name: 'X Layer Preconf',
    nativeCurrency: { name: 'OKB', symbol: 'OKB', decimals: 18 },
    rpcUrls: {
        default: { http: ['https://rpc.xlayer.tech/flashblocks'] },
    },
    blockExplorers: {
        default: { name: 'Explorer', url: 'https://www.oklink.com/xlayer-test' },
    },
    testnet: true,
});

const account = privateKeyToAccount(process.env.PRIVATE_KEY);

const walletClient = createWalletClient({
    account,
    chain: xlayerPreconf,
    transport: http('https://rpc.xlayer.tech/flashblocks'),
});

const publicClient = createPublicClient({
    chain: xlayerPreconf,
    transport: http('https://rpc.xlayer.tech/flashblocks'),
});

async function sendTransaction() {
    try {
        const submissionTime = new Date();
        const hash = await walletClient.sendTransaction({
            to: '0x0000000000000000000000000000000000000001',
            value: BigInt('100000000000000'),
        });

        console.log(`Transaction submitted time: ${submissionTime.toISOString()}`);
        console.log(`Transaction hash: ${hash}`);

        let receipt = null;
        while (!receipt) {
            try {
                receipt = await publicClient.getTransactionReceipt({ hash });
            } catch (e) {
                await new Promise(resolve => setTimeout(resolve, 10));
            }
        }

        const confirmationTime = new Date();
        console.log(`Transaction confirmed time: ${confirmationTime.toISOString()}`);
        console.log(`Time difference: ${confirmationTime.getTime() - submissionTime.getTime()}ms`);
    } catch (error) {
        console.error('Error sending transaction:', error);
    }
}

sendTransaction();
// node src/ViemExample.js
```

--------------------------------

### Configure Hardhat for Manual Verification (X Layer Testnet)

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Modify `hardhat.config.js` to include network settings and Etherscan API configurations for X Layer testnet. Replace placeholders with your actual private key and OKLink API key.

```javascript
module.exports = {
    solidity: "0.8.9",
    networks: {
        xlayer: {
            url: "https://testrpc.xlayer.tech/terigon", //or https://rpc.xlayer.tech for mainnet
            accounts: [process.env.PRIVKEY]
        }
    },
    etherscan: {
        apiKey: process.env.ETHERSCAN_KEY,
        customChains: [
            {
                network: "xlayer",
                chainId: 195, //196 for mainnet
                urls: {
                    apiURL: "https://www.oklink.com/api/v5/explorer/contract/verify-source-code-plugin/XLAYER_TESTNET", //or https://www.oklink.com/api/v5/explorer/contract/verify-source-code-plugin/XLAYER for mainnet
                    browserURL: "https://www.oklink.com/xlayer-test" //or https://www.oklink.com/xlayer for mainnet
                }
            }
        ]
    }
};
```

--------------------------------

### Get Transaction by Block Number and Index

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Retrieves transaction details using the block number and the transaction's index within that block. Use 'pending' for pending blocks.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getTransactionByBlockNumberAndIndex","params":["pending","0x0"],"id":1}'
```

--------------------------------

### Flashblocks Base + Diff Response Example

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

This JSON structure represents a full Flashblocks message, including base block properties and transaction diffs. It is used when the index is 0.

```json
{
  "base": {
    "base_fee_per_gas": "0x5f5e0ff",
    "block_number": "0x8328ab",
    "extra_data": "0x...",
    "fee_recipient": "0x...",
    "gas_limit": "0xbebc200",
    "parent_beacon_block_root": "0x...",
    "parent_hash": "0x...",
    "prev_randao": "0x...",
    "timestamp": "0x695dd9b6"
  },
  "diff": {
    "blob_gas_used": "0x0",
    "block_hash": "0x...",
    "gas_used": "0x6c63",
    "logs_bloom": "0x...",
    "receipts_root": "0x...",
    "state_root": "0x...",
    "transactions": [],
    "withdrawals": [],
    "withdrawals_root": "0x..."
  },
  "index": 0,
  "metadata": {
    "block_number": 8595627,
    "new_account_balances": {
      "0x0000f90827f1c53a10cb7a02335b175320002935": "0x0"
    },
    "receipts": {
      "0x56d542ee662d9a7e1696880346a3f2fb1ed091c15b7c6b607f64ae95e431b097": {
        "Deposit": {}
      }
    }
  },
  "payload_id": "0x03307607ad2ba79d"
}
```

--------------------------------

### Deploy Smart Contract with Forge

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-foundry

Deploys the Counter contract from src/Counter.sol. Replace HTTP_URL and PRIVATE_KEY with your actual RPC endpoint and private key.

```bash
forge create --rpc-url HTTP_URL \
--private-key PRIVATE_KEY \
src/Counter.sol:Counter
```

--------------------------------

### Get Block Number (Testnet)

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/rpc-endpoints/rpc-endpoints

Use this curl command to retrieve the latest block number from the X Layer testnet RPC endpoint. Ensure you are using the correct testnet URL.

```shell
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}' -H "Content-Type: application/json" https://testrpc.xlayer.tech/terigon
```

--------------------------------

### Compile Smart Contracts with Hardhat

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-hardhat

Use this command to compile your Solidity smart contracts. Hardhat will process the contract files and generate the necessary artifacts.

```shell
npx hardhat compile
```

--------------------------------

### Get Block Number (Mainnet)

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/rpc-endpoints/rpc-endpoints

Use this curl command to retrieve the latest block number from the X Layer mainnet RPC endpoint. Ensure you are using the correct mainnet URL.

```shell
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}' -H "Content-Type: application/json" https://rpc.xlayer.tech
```

--------------------------------

### Live Test: eth_getTransactionReceipt via Flashblocks RPC

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Perform a live test by querying the `eth_getTransactionReceipt` method on the public X Layer Flashblocks RPC endpoint. Replace the transaction hash placeholder with a valid hash.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getTransactionReceipt","params":["0x..."],"id":1}'
```

--------------------------------

### Get Current Flashblocks Pending Block Height

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/overview

Use this command to query the current pending block height from Flashblocks-enabled RPC endpoints. Ensure you are using the 'pending' tag for the query.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":["pending"],"id":1}'
```

--------------------------------

### Compile Smart Contracts with Truffle

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-truffle

Compile your Solidity smart contracts using the Truffle framework. Ensure you are in the root directory of your Truffle project before running this command.

```shell
truffle compile
```

--------------------------------

### Java: Address Conversion and Validation

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Demonstrates converting between XKO and EVM addresses, checking for Xlayer addresses, and handling invalid address formats using the Java SDK.

```java
import com.okcoin.MultiAddress;

public class Example {
    public static void main(String[] args) {
        // XKO to EVM
        String evmAddr = MultiAddress.toEvmAddress("XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625");
        System.out.println(evmAddr);
        // Output: 0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625

        // EVM to XKO
        String xkoAddr = MultiAddress.fromEvmAddress("0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625");
        System.out.println(xkoAddr);
        // Output: XKO70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625

        // Check if XKO address
        boolean isXko = MultiAddress.isXlayerAddress("XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625");
        System.out.println(isXko); // true

        boolean isNotXko = MultiAddress.isXlayerAddress("0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625");
        System.out.println(isNotXko); // false

        // Error handling
        try {
            MultiAddress.toEvmAddress("invalid");
        } catch (IllegalArgumentException e) {
            System.err.println(e.getMessage());
            // Output: Invalid address length: expected 40 hex chars, got 7
        }
    }
}
```

--------------------------------

### Run Deployment Script on X Layer Network

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-hardhat

Execute the deployment script using `npx hardhat run` and specify the `--network XLayer` flag to deploy the contract to the X Layer network.

```shell
$ npx hardhat run scripts/deploy.js --network XLayer
```

--------------------------------

### Configure Hardhat for X Layer Network

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-hardhat

Set up your `hardhat.config.js` file to include the X Layer network details. This involves specifying the network URL and accounts for deployment.

```javascript
module.exports = {
  defaultNetwork: "hardhat",
  networks: {
    hardhat: {
    },
    xlayer: {
      url: "https://testrpc.xlayer.tech/terigon",
      accounts: [privateKey1, privateKey2, ...]
    }
  }
}
```

--------------------------------

### Verify TransparentUpgradeableProxy Contract

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Use this command to verify TransparentUpgradeableProxy contracts. Specify the contract details and the proxy address.

```bash
npx hardhat okxverify --network xlayer --contract <Contract>:<Name> --proxy <address>
```

--------------------------------

### Live Test: eth_getTransactionCount via Flashblocks RPC

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Perform a live test by querying the `eth_getTransactionCount` method on the public X Layer Flashblocks RPC endpoint. Replace the address placeholder with a valid address.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getTransactionCount","params":["0x...","pending"],"id":1}'
```

--------------------------------

### eth_estimateGas RPC Method

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

This snippet demonstrates how to estimate gas for a transaction using the eth_estimateGas method via the Flashbots RPC. Provide the correct 'to' and 'data' for accurate estimation.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_estimateGas","params":[{"to":"0x...","data":"0x..."},"pending"],"id":1}'
```

--------------------------------

### Deploy Contract with Truffle

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-truffle

Run this command in the root of your project directory to deploy your contract to the X Layer Chapel Testnet.

```shell
$ truffle migrate --network testnet
```

--------------------------------

### Define X Layer Chains with Viem

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/builder-codes/integration

Define the X Layer mainnet and testnet configurations using Viem's `defineChain` function. This allows you to reuse these configurations across your project.

```typescript
import { defineChain } from "viem";

// Mainnet
export const xlayer = defineChain({
  id: 196,
  name: "X Layer",
  nativeCurrency: { name: "OKB", symbol: "OKB", decimals: 18 },
  rpcUrls: {
    default: { http: ["https://rpc.xlayer.tech"] },
  },
  blockExplorers: {
    default: { name: "OKLink", url: "https://www.oklink.com/xlayer" },
  },
});

// Testnet
export const xlayerTestnet = defineChain({
  id: 1952,
  name: "X Layer Testnet",
  nativeCurrency: { name: "OKB", symbol: "OKB", decimals: 18 },
  rpcUrls: {
    default: { http: ["https://testrpc.xlayer.tech"] },
  },
  blockExplorers: {
    default: { name: "OKLink", url: "https://www.oklink.com/x-layer-testnet" },
  },
});
```

--------------------------------

### Live Test: eth_getTransactionByHash via Flashblocks RPC

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Perform a live test by querying the `eth_getTransactionByHash` method on the public X Layer Flashblocks RPC endpoint. Replace the transaction hash placeholder with a valid hash.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["0x..."],"id":1}'
```

--------------------------------

### Sample Lock.sol Contract

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/deploy-a-smart-contract/deploy-with-hardhat

A basic Solidity contract demonstrating state variables, events, a constructor, and a withdraw function. It includes checks for unlock time and owner.

```solidity
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;

// Uncomment this line to use console.log
// import "hardhat/console.sol";

contract Lock {
    uint public unlockTime;
    address payable public owner;

    event Withdrawal(uint amount, uint when);

    constructor(uint _unlockTime) payable {
        require(
            block.timestamp < _unlockTime,
            "Unlock time should be in the future"
        );

        unlockTime = _unlockTime;
        owner = payable(msg.sender);
    }

    function withdraw() public {
        // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
        // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);

        require(block.timestamp >= unlockTime, "You can't withdraw yet");
        require(msg.sender == owner, "You aren't the owner");

        emit Withdrawal(address(this).balance, block.timestamp);

        owner.transfer(address(this).balance);
    }
}
```

--------------------------------

### Live Test: eth_getBlockByNumber via Flashblocks RPC

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/flashblocks/node-providers

Perform a live test by querying the `eth_getBlockByNumber` method on the public X Layer Flashblocks RPC endpoint. Replace placeholders with your actual parameters.

```shell
curl https://rpc.xlayer.tech/flashblocks -X POST -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["pending",true],"id":1}'
```

--------------------------------

### Rust: Convert XKO to EVM and EVM to XKO Addresses

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Use the Rust SDK to convert between XKO and EVM address formats. Handles potential errors during conversion.

```rust
use multi_address::{to_evm_address, from_evm_address};

fn main() {
    // XKO to EVM
    match to_evm_address("XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625") {
        Ok(evm_addr) => println!("{}", evm_addr),
        // Output: 0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
        Err(e) => eprintln!("Error: {}", e),
    }

    // EVM to XKO
    match from_evm_address("0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625") {
        Ok(xko_addr) => println!("{}", xko_addr),
        // Output: XKO70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625
        Err(e) => eprintln!("Error: {}", e),
    }
}
```

--------------------------------

### TypeScript SDK: Type-Safe Address Conversion

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/build-on-xlayer/address-format

Demonstrates type-safe address conversion between XKO and standard EVM formats using the TypeScript SDK. Shows how TypeScript enforces correct input types.

```typescript
import { toEvmAddress, fromEvmAddress } from './multiAddress';

// Type-safe address conversion
const evmAddr: string = toEvmAddress('XKO70586beeb7b7aa2e7966df9c8493c6cbfd75c625');
const xkoAddr: string = fromEvmAddress('0x70586BeEB7b7Aa2e7966DF9c8493C6CbFd75C625');

// Type checking
toEvmAddress(123); // TypeScript compile error
```

--------------------------------

### Verify Smart Contract with Foundry and OKLink

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-foundry

Use this command to verify your deployed smart contract. Provide the contract address, contract name or path, and the OKLink verification URL. The `--verifier oklink` flag specifies the verifier service.

```javascript
forge verify-contract <the_contract_address>
      src/MyToken.sol:MyToken  
      --verifier oklink 
      --verifier-url oklinkverifyUrl

```

--------------------------------

### Deploy Contract using Hardhat

Source: https://web3.okx.com/zh-hans/xlayer/docs/developer/verify-a-smart-contract/verify-with-hardhat

Compile and deploy your Hardhat contract to the specified network. This command is used before the verification step.

```javascript
hh run scripts/deploy.js --network xlayer
```