Field Guide to Bridges
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Transferring assets between blockchains is not necessarily a simple task. Some tokens cannot be sent from one network to another — and if you do, you can lose them forever.
What is a bridge?
A bridge is an app that allows you to transfer assets (cryptocurrencies, NFTs, or other tokens) between one blockchain and another. For example, transferring from BSC (now BNB Chain) to Ethereum.
Why do I need to use a bridge?
- Many users use the same address on multiple blockchains, for example by adding a blockchain connection in MetaMask. What if they've got an NFT on Gnosis Chain, but they want to have it on Polygon?
- Conversely, you might have a different address, say on BSC, than what you use on Ethereum. You may think that you can just send tokens from your BSC address directly to your Ethereum address; after all, they're both EVM-compatible, right?
Wrong. The BSC blockchain and Ethereum blockchains are separate networks, with no built-in knowledge of each other.
If you send to your Ethereum address from BSC, BSC will send to the address you put in, but on the BSC network. For more information on this specific scenario, see here.
What bridge should I use?
You can now access a curated, straightforward bridging experience in MetaMask Bridge, available at portfolio.metamask.io, or by clicking the 'Bridge' button in MetaMask Extension. Only certain tokens and network combinations are available initially.
You should choose a bridge primarily based on what you're trying to move, where. For example, some bridges only move ERC-20 (currency) tokens; others specifically handle ERC-721 and 1155 (NFTs). The last thing you want to do is try to transfer tokens to a different network, and never receive them.