Browser Extension Wallet

Browser Extension Wallet - SDK

Prerequisites

If you haven’t downloaded the KC Wallet browser extension yet, please go to the download page:

If you have already installed the extension, check whether it is running properly in your browser. Copy the following code into the browser Developer Console:

If it runs correctly, proceed to the next step.

EVM Chains

Standard Wallet Methods

Method	Params	Return Type	Description
-	()	Promise	method; returns account
-	-	-	Gets connection currently always
request	(payload)	-	payload.method can be personal_sign, eth_sendTransaction execution
-	-	-	Whether Dapp (TBD; currently always)
-	-	-	String representation

Create Connection

To connect a wallet, you can initiate a “wallet connection” using the code below by calling eth_requestAccounts to access the user’s account address.

Listen for Account Address Changes

You can listen for changes via events:

Whenever the return value of the eth_accounts RPC method changes, KC Wallet emits the corresponding event to notify the DApp of address changes. eth_accounts returns either an empty array or an array containing a single account address. If present, the returned address is the most recently used account address that the caller is permitted to access.

Because callers are identified by their URL origin, sites with the same origin share the same permissions. Whenever the user’s exposed account address changes, accountsChanged will be emitted.

Get chainId

All RPC requests are submitted to the currently connected network, so accurately obtaining the user’s chain ID is critical for EVM-based application development.

Use eth_chainId to get the user’s current chain ID:

Listen to the chainChanged event to detect network changes:

Chain IDs

Below are the Ethereum-compatible chain IDs supported by KC Wallet by default. For more information, see chainid.network.

Hex	Network
0x1	Ethereum Main Network (Mainnet)
0x4115	-
0xa86a	43114 Avalanche C
0x2105	8453 Base
0x8f	143 Monad
0x279f	10143 Monad Testnet
0x89	137 Polygon
0x13a7	5031 Sonnia
0xc4	196 X Layer

Switch Chain

To switch the chain that the wallet and DApp are connected to, use the example below:

Message Signing

Sign Arbitrary Messages

personal_sign (often referred to as signPersonalMessage ) is used to sign arbitrary text messages with the user’s Ethereum private key.

Sign Structured Data

eth_signTypedData (specifically eth_signTypedData_v4 ) is used to sign structured data according to the EIP-712 standard. This standard enables applications to create cryptographic signatures for complex, structured data, ensuring signatures are both human-readable and verifiable.

Sign Transactions

A transaction is a formal action on the blockchain. In KC Wallet, transactions must be initiated by calling eth_sendTransaction . Transactions may involve simple ETH transfers, token transfers, deploying a new smart contract, or changing on-chain state in any manner. Such transactions must be initiated with a signature from an externally owned account (or a simple keypair).

In KC Wallet, you can initiate a transaction via kcwallet.request .

Parameters

This section introduces transaction parameters covered in this document. Most transaction parameters in this document are handled by OKX Wallet. Transactions are divided into legacy transactions and EIP-1559 transactions, described below.

Legacy Transaction

EIP-1559 Transaction

For EIP-1559 transactions, the key difference from legacy transactions is that maxPriorityFeePerGas and maxFeePerGas are used instead of gasPrice.

maxPriorityFeePerGas (optional): An additional tip the user is willing to pay to the miner/validator to incentivize prioritizing the transaction.

maxFeePerGas (optional): The maximum total fee per unit of gas the user is willing to pay, including both the base fee and the priority fee.

Browser Extension Wallet