Docs · method · EVM

`eth_chainId`

Facts for eth_chainId
Units per call	1 (standard)
Cache	static — 1 week, a hit costs 0 units
Rule	1 unit on a miss; per-chain constant, cached a week.
Chains	Ethereum Mainnet · Base Mainnet · Arbitrum One · OP Mainnet · Polygon PoS
Specification	https://ethereum.github.io/execution-apis/api-documentation/

Example

curl -s https://flexyield.io/rpc/eth_mainnet \
  -H "Authorization: Bearer $FLEXYIELD_KEY" -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'

Questions

Is eth_chainId cached?

Yes — a per-chain constant, cached 1 week; hits cost 0 units.

All methods: methods and limits · docs · AI agents: the same call is the rpc_call MCP tool.