net_version

net_version returns the network ID of the chain the node is connected to, as a decimal string. For Arbitrum One — the Optimistic Rollup that settles to Ethereum and pays gas in ETH — that value is "42161", matching its chain ID (42161, or 0xa4b1 in hex). Querying https://arbitrum.therpc.io/YOUR_API_KEY with this no-parameter method is a fast way to confirm a connection is pointed at Arbitrum One mainnet and not at the Sepolia testnet or another chain entirely before you act on the node's data.

Use cases

• Verify that a wallet or dApp is connected to the expected network — confirm "42161" for Arbitrum One mainnet — before submitting a transaction, so funds and contract calls land on the right chain.
• Differentiate mainnet ("42161") from the Arbitrum Sepolia testnet ("421614") in environment-aware application logic, so staging and production code paths read the network straight from the node.

Parameters

此方法不需要任何参数，传入空数组 [] 即可。

Response

Example request

1curl https://arbitrum.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "net_version",
7    "params": [],
8    "id": 1
9  }'

Try it live in the Arbitrum One playground.

Errors & troubleshooting

Common pitfalls

• Network ID and chain ID happen to coincide for Arbitrum One (both 42161), but they are not the same concept and can differ on other networks. Always use eth_chainId — not net_version — for the value you fold into transaction signing and EIP-155 replay protection.
• The value comes back as a decimal string ("42161"), not a hex-encoded number like most other numeric RPC responses. Do not pass it through hex parsing, or you will misread the network.

Supported networks

• Mainnet — Chain ID: 42161
• Sepolia — Chain ID: 421614

See also

• eth_chainId
• net_listening
• net_peerCount

1curl https://arbitrum.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"net_version","params":[]}'