Skip to main content

wallet_addEthereumChain

MetaMask

Creates a confirmation asking the user to add the specified chain to the wallet application. The caller must specify a chain ID and some chain metadata. The wallet application may refuse or accept the request. null is returned if the chain is added, and an error otherwise. Introduced by EIP-3085.

Params

(1)

1. AddEthereumChainParameter (required)

chainId
string
required

The chain ID as a 0x-prefixed hexadecimal string, per the eth_chainId method. MetaMask compares this chain ID value with the eth_chainId return value. If these values aren't identical, MetaMask rejects the request.

blockExplorerUrls
array[string]

(Optional) One or more URLs pointing to block explorer sites for the chain.

chainName
string
required

A human-readable name for the chain.

iconUrls
array[string]<uri>

(Optional) One or more URLs pointing to reasonably sized images that can be used to visually identify the chain.

nativeCurrency
NativeCurrency
required

Describes the native currency of the chain using the name, symbol, and decimals fields.

decimals
integer
required

A non-negative integer.

name
string

A human-readable name.

symbol
string
required

A human-readable symbol.

rpcUrls
array[string]<uri>
required

One or more URLs pointing to RPC endpoints that can be used to communicate with the chain. At least one item is required, and only the first item is used.

>= 1 items

Result

(AddEthereumChainResult)
null

Errors

CodeMessage
-32602Expected null or array with at least one valid string HTTPS URL 'blockExplorerUrl'. Received: ${blockExplorerUrls}
-32602Expected 0x-prefixed, unpadded, non-zero hexadecimal string 'chainId'. Received: ${chainId}
-32602Invalid chain ID "${_chainId}": numerical value greater than max safe value. Received: ${chainId}
-32602May not specify default MetaMask chain.
-32602Expected 2-6 character string 'nativeCurrency.symbol'. Received: ${ticker}
-32602nativeCurrency.symbol does not match currency symbol for a network the user already has added with the same chainId. Received: ${ticker}

Example

Request

await window.ethereum.request({
"method": "wallet_addEthereumChain",
"params": [
{
"chainId": "0x64",
"chainName": "Gnosis",
"rpcUrls": [
"https://rpc.ankr.com/gnosis"
],
"iconUrls": [
"https://xdaichain.com/fake/example/url/xdai.svg",
"https://xdaichain.com/fake/example/url/xdai.png"
],
"nativeCurrency": {
"name": "xDAI",
"symbol": "xDAI",
"decimals": 18
},
"blockExplorerUrls": [
"https://blockscout.com/poa/xdai/"
]
}
]
});

Result

"null"

Params

AddEthereumChainParameter

blockExplorerUrls
iconUrls
NativeCurrency*
rpcUrls*

Request

await window.ethereum.request({
"method": "wallet_addEthereumChain",
"params": [
null
]
});