net_version

net_version returns the network ID of the chain a node is connected to as a decimal string. On OP Mainnet — the OP Stack rollup that settles to Ethereum L1 and uses ETH for gas — this returns "10", matching the chain ID. It is a fast way for a wallet or backend to confirm it is talking to the right network before acting. Call it at https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa) and you get the decimal string "10" back.

Use cases

• Confirm a wallet or dApp is connected to OP Mainnet (network ID 10) before submitting a transaction, guarding against accidental sends on the wrong chain.
• Distinguish OP Mainnet (10) from OP Sepolia (11155420) in environment-aware logic that picks contract addresses and config per network.

Parameters

This method takes no parameters. Pass an empty array [].

Response

Example request

1curl https://optimism.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 Optimism playground.

Errors & troubleshooting

Common pitfalls

• Network ID and chain ID happen to coincide on OP Mainnet (both 10), but that is not guaranteed on every network — always use eth_chainId for the value you fold into EIP-155 transaction signing.
• The result is a decimal string ("10"), not a 0x-prefixed hex value like most other numeric RPC responses, so parse it accordingly.

Supported networks

• Mainnet — Chain ID: 10
• Sepolia — Chain ID: 11155420

See also

• eth_chainId
• net_listening
• net_peerCount

1curl https://optimism.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":[]}'