What is a Chain ID? A Chain ID is a unique number that identifies a specific blockchain network, helping wallets, apps, and transactions know which chain they are interacting with.
Chain ID Explained A Chain ID is like an ID number for a blockchain.
Different blockchains can look similar, especially if they use the same technology. A Chain ID helps tell them apart.
For example, Ethereum mainnet has one Chain ID, while a test network or another EVM-compatible chain has a different one.
This matters because transactions must happen on the correct network. The Chain ID helps prevent apps or wallets from confusing one blockchain with another.
What a Chain ID Means For Audience
Use Case
Crypto users
Confirm they are connected to the correct network before sending assets or using apps.
Developers
Configure wallets, apps, smart contracts, and infrastructure for the right blockchain network.
Protocol and support teams
Help users troubleshoot wrong-network errors, failed transactions, or missing assets.
Examples A user adds a new EVM network to their wallet and enters the correct Chain ID so the wallet connects to the right blockchain.
A developer configures an app to use Ethereum mainnet’s Chain ID for real transactions and a testnet Chain ID for testing.
A wallet warns a user when they are connected to the wrong Chain ID for the app they are trying to use.
A support team asks for the user’s network and Chain ID to check whether their transaction happened on the intended chain.
FAQs What is a Chain ID used for? A Chain ID identifies which blockchain network a wallet, app, or transaction is using.
Is Chain ID the same as network name? No. The network name is human-readable. The Chain ID is the unique numeric identifier.
Why does Chain ID matter? It helps prevent wallets and apps from confusing one blockchain network with another.
Can two chains have the same Chain ID? They should not. Shared Chain IDs can cause wallet, app, and transaction confusion.
Where do I find a Chain ID? You can usually find it in wallet network settings or blockchain network documentation.