EVM Chain ID Reference

When you need to configure MetaMask, write a Hardhat config, or debug a transaction that silently landed on the wrong network, the first thing you reach for is the chain ID. The EVM Chain ID Reference puts 59 networks in one searchable table: every major mainnet, the current testnets, the leading L2s, and the five legacy testnets (Göerli, Mumbai, Rinkeby, Ropsten, Kovan) marked deprecated so you know not to build on them. Click any chain ID, currency symbol, or RPC URL and it copies to your clipboard.

Type into the search box and the table filters live across name, chain ID number, currency ticker, short name, and RPC hostname. Searching 421 lands on both Arbitrum One (42161) and Arbitrum Sepolia (421614). Searching ETH returns every network whose native currency is ETH — handy for confirming that an L2 you are bridging to shares Ethereum's unit, not a wrapped variant. The five type-filter tabs (Mainnets, L2s, Sidechains, Testnets, Deprecated) narrow the list further; they combine with the search box so you can show only Testnet rows that match base.

The data is bundled at build time, so the tool works offline and never makes a network request. For the authoritative live registry of every EVM-compatible chain see chainlist.org, sourced from the open ethereum-lists/chains registry. This tool covers the 59 networks developers encounter most, not all 800+.

What Each Column Shows

• Chain ID: the chainId field your wallet, RPC provider and contract code use to identify the network. This is the number you add to MetaMask's “Add Network” form and the value Solidity reads from block.chainid. Click to copy.
• Name and short name: the human label followed by the EIP-3770 short name in monospace (e.g. arb1 for Arbitrum One, oeth for OP Mainnet). The short name prefixes addresses in multi-chain address standards.
• Currency: the ticker of the native gas token. Bridged ETH on L2s still appears as ETH, which is why Base, Arbitrum and OP Mainnet show the same symbol as Ethereum despite being separate networks. Click to copy.
• Public RPC: a free, unauthenticated endpoint for read-only calls and development use. Rate limits vary by provider; for production workloads use a dedicated node service. Click to copy the full URL. Deprecated networks show no RPC because their public endpoints have been shut down.
• Explorer: the canonical block explorer for the chain. Opens in a new tab with rel="noopener noreferrer".

Edge Cases: Where Chain IDs Go Wrong

• Chain ID 1 is Ethereum Mainnet. Any local development chain (Hardhat, Anvil, Ganache) that defaults to ID 1 looks identical to mainnet to MetaMask, which is the usual cause of “wrong network” errors in development. Hardhat and Anvil both default to 31337 precisely to avoid this.
• EIP-155 introduced replay protection by including the chain ID in the transaction signature. A transaction signed for chain ID 1 is invalid on chain ID 137. The chain ID is not a label; it changes the bytes that go on-chain, and submitting a cross-chain transaction fails silently rather than reverting.
• Some testnets reused a chain ID after deprecation. Kovan (42) is the most common collision: several smaller sidechains launched with the same ID. Always verify the RPC hostname matches what your wallet reports when accepting “Add Network” requests.
• Harmony's chain ID (1666600000) exceeds the range of a 32-bit unsigned integer. Tools built before EIP-155 or hard-coded to 32-bit ints reject it. Modern EVM tooling handles BigInt chain IDs correctly from version 6 of ethers.js and Hardhat 2.10+.