My wallet showed one address. My brain assumed one balance. So when a friend said “send it on Arbitrum, fees are cheaper,” I did — from the Ethereum mainnet screen I already had open. The transaction succeeded. The money was not where anyone expected. Welcome to networks.
Separate ledgers, same face
A network is its own blockchain: own history, own validators, own gas token. Ethereum mainnet and Arbitrum both use EVM-style addresses, so 0x… looks identical. But ETH sitting on mainnet is not automatically on Arbitrum. Think same house number, different cities.
Layer 1 is the base settlement layer — Ethereum, Bitcoin, Solana. Layer 2s like Optimism and Base batch transactions and anchor security back to L1, trading speed and cost for an extra hop of complexity.
Bridges — the part nobody demos on day one
Moving between networks means a bridge: lock tokens on one chain, mint a representation on another. Official L2 bridges are boring and slow — which is a feature. Random “fast bridges” are where people learn expensive lessons.
I spent a weekend tracing wrapped tokens on a block explorer before I trusted that my coins still existed somewhere. They did. I just hadn’t finished the map in my head.
The network dropdown in your wallet isn’t cosmetic. It’s which universe you’re about to sign a transaction in.
How I think about it now
Before I send anything: network, address, gas token. Three checks. Mainnet for big, slow, expensive, battle-tested. L2s for frequent small moves. Bitcoin and Solana are different animals entirely — not EVM, not interchangeable.
Sending to the right address on the wrong network can mean stuck funds or unrecoverable loss depending on the pair. If you’re unsure, send a test amount and watch it arrive on a block explorer before moving size.
Networks stopped being abstract the day I had to explain to a friend why his “Ethereum” wasn’t showing up on the app he opened. Same confusion I’d had. At least now I have words for it.