A network (also called a chain) is an independent blockchain: its own transaction history, validators, and rules. “Ethereum” and “Arbitrum” are different networks even though they share EVM compatibility.
The main categories
| Type | Examples | Role |
|---|---|---|
| Layer 1 (L1) | Ethereum, Bitcoin, Solana | Base security and settlement |
| Layer 2 (L2) | Arbitrum, Optimism, Base | Cheaper transactions, settled back to L1 |
| Sidechain | Polygon PoS (legacy) | Separate validators, bridge to L1 |
| App-chain | dYdX, Hyperliquid | Chain optimised for one platform |
Bitcoin is its own L1 with a different model (no general-purpose smart contracts). Solana is a separate L1 with a different virtual machine — not EVM.
Same address, different balances
On EVM chains, your wallet address (e.g. 0xabc…) is identical everywhere. But ETH on Ethereum mainnet is not ETH on Arbitrum in the sense of a shared balance — each network tracks holdings separately.
Your wallet UI switches networks via a dropdown. Sending a transaction on the wrong network is a common beginner mistake: the transaction may fail, or assets may end up on a chain you didn’t intend.
Bridging between networks
To move assets from Ethereum to an L2 (or back), you use a bridge — a smart contract or service that locks tokens on one side and mints a representation on the other.
Bridging risks include:
- Smart contract bugs in the bridge
- Delays during congestion
- Wrapped tokens that may not redeem 1:1 in a crisis
Official bridges from L2 teams are generally preferred over anonymous third-party bridges.
Before any transaction, confirm three things in your wallet: the correct network, the correct recipient address, and that you have enough of the native gas token (ETH on Ethereum, ETH on Arbitrum, MATIC on Polygon, etc.).