eth_chainId | Alchemy Docs

Returns the chain ID of the current network as a hexadecimal string.

apiKeystringRequired

The chain ID of the current network in hexadecimal format.

1	curl -X POST https://arb-mainnet.g.alchemy.com/v2/{apiKey} \
2	-H "Content-Type: application/json" \
3	-d '{
4	"jsonrpc": "2.0",
5	"method": "eth_chainId",
6	"params": [],
7	"id": 1
8	}'