Every blockchain charges a fee (gas) to process transactions. Those fees pay validators for securing the network. When you swap on Chain X, you must hold Chain X’s native token to cover gas:
| Chain | Fee Token |
| Ethereum Mainnet | ETH |
| Polygon PoS | POL |
| BNB | BNB |
| Arbitrum | ARBETH (ETH) |
| Optimism | OETH (ETH) |
| Base | BASEETH (ETH) |
| Bitcoin | BTC |
| Solana | SOL |
| Avalanche C-Chain | AVAX |