Chain ID
Protocol
Numeric identifier that distinguishes EVM networks.
The chain ID is a number that marks which EVM network a transaction belongs to. It protects against replay attacks and helps wallets route requests to the right chain.
Frequently asked questions
Why does the chain ID matter?
It prevents replay attacks by making signatures valid only on the intended network.Where do I find a chain ID?
Wallets and docs list them. For Ethereum Mainnet it is 1. Testnets and L2s have different IDs.What if I use the wrong chain ID?
Transactions will be rejected or sent to the wrong network. Always check your wallet network before signing.