They pay network validators to process and confirm transactions.
They prevent spam by requiring a cost for using the network.
Fees vary depending on network congestion and transaction complexity.
For example:
Sending ETH = simple transaction = low gas
Minting an NFT or executing a smart contract = complex = higher gas
Gas fees are denominated in the blockchain’s native currency (e.g., ETH on Ethereum, MATIC on Polygon).
Use Layer 2 solutions (e.g., Arbitrum, Optimism)
Choose less congested times to transact
Set custom gas limits or use platforms with dynamic fee estimators
Some chains (like Solana or Avalanche) offer near-zero fees, which is why they’re popular for high-volume apps.