Gas and fees
Sei supports both legacy and EIP-1559 transactions. However, the fee model differs from Ethereum in three ways that affect how you estimate and set gas.
Legacy gas price floor
Legacy transactions (type 0) on Sei must meet a minimum gas price set by on-chain governance. Governance proposals can change this floor, so do not hard-code a specific value.
To read the current minimum, use eth_gasPrice:
EIP-1559 fee model
Sei supports EIP-1559 transactions (type 2), but it does not burn the base fee. All fees go to validators. On Ethereum, part of the fee is burned.
This does not affect how you construct or send transactions. maxFeePerGas and maxPriorityFeePerGas work as expected. It matters only if your application models token supply or shows fee-burn information to users.
Effective gas price on receipts
For dynamic-fee (type 2) transactions, the effectiveGasPrice field of the transaction receipt reports the actual price charged, not the fee cap. That price is min(baseFee + maxPriorityFeePerGas, maxFeePerGas). This matches standard EIP-1559 semantics. Clients such as ethers and Hardhat therefore see the same effectiveGasPrice behavior that they expect from Ethereum.
In practice, when your priority tip plus the base fee stays below maxFeePerGas, the receipt reports baseFee + maxPriorityFeePerGas, not maxFeePerGas. To compute what a transaction paid, use the receipt’s effectiveGasPrice, not maxFeePerGas.
SSTORE cost
On Sei, governance can adjust the gas cost of SSTORE (a write to contract storage). The current cost is 72,000 gas on both Sei Mainnet and Sei Testnet. For details, see Differences with Ethereum. Treat this number as the current value, not a constant. Do not hard-code storage write estimates in your application.
Always use eth_estimateGas for any transaction that writes to storage:
Estimate the absolute storage-write cost with a live eth_estimateGas call against a Sei RPC. A Foundry forge test --gas-report --fork-url <sei rpc> report forks the chain state, but it runs the standard EVM gas schedule of revm. It therefore shows SSTORE at the Ethereum cost (approximately 22,100) instead of the Sei cost (approximately 72,000). Use the report for relative profiling of your own logic.
Summary