Networks, layer 2s and bridges: why the chain you send on matters

What a network is

A blockchain network is a shared ledger kept by its own set of computers, with its own rules and its own coin for fees: ETH on Ethereum, TRX on TRON, BNB on BNB Smart Chain, SOL on Solana, POL on Polygon. Each network knows only its own ledger: a balance on TRON is invisible to Ethereum.

Tokens such as USDT and USDC are programs, called smart contracts, running on a network. An issuer deploys a separate contract on each network it supports, and each copy can only move within its own network.

The version matters too: some copies come from Tether or Circle, others from a third party that backs them with tokens it holds elsewhere.

USDT0 is run by Everdawn Labs, a separate company, and backed one-for-one by USDT locked on Ethereum. Some networks also carry bridged versions, such as "USDC.e", that Circle neither issues nor backs.

Why the wrong network can cost you

Networks built on Ethereum's technology, including BNB Smart Chain, Polygon and Base, share one address format, and one key controls the same address on all of them. So your wallet will happily send USDT on BNB Smart Chain to an address the recipient gave you for Ethereum. The transfer succeeds, but the tokens land on BNB Smart Chain, where the recipient may never look.

What happens next depends on who controls the address:

• Your own wallet: if you hold the keys, switch the wallet to the network you used and the tokens should be there.
• An exchange or payment service: recovery is at its discretion, and not always possible.
• A smart-contract wallet, such as a multisig: it may exist on one network only, so funds sent to its address elsewhere can be stuck.

Between different formats, wallets usually catch the mistake: a TRON address isn't valid on Ethereum. The subtler trap is the right network but the wrong token version, which a service may not credit.

Address formats, network by network

Each family of networks has its own address shape:

Many 0x addresses mix capital and small letters: that pattern is a checksum, so a wallet that checks it will almost always catch a typo. Bittensor is the network behind the TAO token, explained in our Bittensor guide.

A careful wallet checks this for you: nowcoin, for example, checks an address's format for the network you've chosen before it lets you send.

Memos on Stellar

Exchanges usually keep all their customers' Stellar funds in one shared account and tell deposits apart by a memo, a short note attached to the transaction, or by a "muxed" address starting with M. If a service gives you a memo, include it exactly: without it, the deposit reaches the exchange but can't be credited to you automatically.

Layer 2s: rollups that settle on Ethereum

Ethereum's own site defines a layer 2 as "a separate blockchain that extends Ethereum and inherits the security guarantees of Ethereum". The most common kind is the rollup. It executes transactions on its own chain, bundles hundreds of them together and posts them to Ethereum, so many users share the cost of one Ethereum transaction.

"Settles on Ethereum" means the rollup's transaction data and results are written to Ethereum, where a contract has the last word on who owns what. Reverting a rollup transaction would then mean reverting Ethereum. And if the rollup's operator disappears, users can in principle rebuild its state from that data and withdraw.

The two main kinds differ in how their results are checked:

"In principle" matters. L2BEAT rates rollups' maturity in stages: Stage 0 is "fully controlled by few entities", Stage 2 is "fully controlled by code", and Stage 1 sits in between. As of late September 2026, the three largest rollups, Base, Arbitrum One and OP Mainnet, are Stage 1: users can exit even if operators misbehave, but a security council can still step in. Only a few small projects have reached Stage 2.

Not everything called a layer 2 is a rollup. L2BEAT describes Polygon PoS as a "proof of stake sidechain for Ethereum", secured by its own validators. BNB Smart Chain, TRON and Solana are independent layer 1 blockchains.

Bridges and their risks

A bridge moves value between networks that can't talk to each other directly. The classic design locks tokens on one chain and issues matching "wrapped" tokens on the other.

Every wrapped token is only as good as the locked collateral and whoever guards it. Ethereum's site separates "trusted" bridges, which rely on an operator, from "trustless" ones that run on smart contracts and algorithms. All carry smart-contract risk; trusted bridges add the risk that operators censor or steal funds.

Some issuers avoid the pool of locked tokens. Circle's Cross-Chain Transfer Protocol burns USDC on one chain and mints it on the other, "without traditional bridge liquidity pools".

Pools of collateral make bridges prime targets, as 2022 showed:

• Wormhole, February 2022: a flaw in signature checks on the Solana side let an attacker mint 120,000 wrapped ETH with nothing behind them. Wormhole's parent company, Jump Trading, replaced the stolen ETH.
• Ronin, March 2022: attackers took control of five of the nine validator keys guarding the bridge between Ethereum and Ronin, the chain behind the game Axie Infinity, and withdrew 173,600 ETH and 25.5 million USDC.

How to choose a network

1. Start with the recipient. Exchanges list the networks they accept for each coin, and every deposit address belongs to one of them. If you're paying a person, ask which network their wallet uses.
2. Check the token version. Where several versions exist, send the one the recipient credits.
3. Look at the fee, and keep the fee coin. Fees differ by network and change with demand, so check the quote before you confirm. You always need a little of the network's own coin, such as ETH on Base or TRX on TRON.
4. Think about speed. Most networks confirm in seconds to minutes. Leaving an optimistic rollup through its official bridge takes about a week; faster routes exist, with risks of their own.
5. Skip unnecessary hops. Every bridge adds fees, waiting and risk. If the recipient accepts the network your coins are already on, use it.

A checklist before every transfer

1. The network matches the one the recipient named for this address.
2. The token is the version the recipient accepts.
3. The address has the right shape for that network, and you've read all of it, not just the first and last characters.
4. You copied it from the recipient or your address book, never from your transaction history, where scammers plant look-alike addresses with tiny transfers.
5. Any memo or tag the service asked for is included exactly.
6. You hold enough of the network's coin for the fee.
7. For a large amount, a small test transfer has arrived first.
8. You've kept the transaction ID until the funds are credited.