Gas and Fees
Sei supports both legacy and EIP-1559 transactions, but 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. This floor can change via governance proposals — do not hard-code a specific value.
Use eth_gasPrice to read the current minimum:
EIP-1559 Fee Model
Sei supports EIP-1559 transactions (type 2), but does not burn the base fee. Fees go entirely to validators rather than being partially burned as on Ethereum.
This does not affect how you construct or send transactions — maxFeePerGas and maxPriorityFeePerGas work as expected. It is relevant only if your application models token supply or displays fee-burn information to users.
Effective Gas Price on Receipts
For dynamic-fee (type 2) transactions, the transaction receipt’s effectiveGasPrice field reports the actual price charged — min(baseFee + maxPriorityFeePerGas, maxFeePerGas) — not the fee cap. This matches standard EIP-1559 semantics, so clients such as ethers and hardhat see the same effectiveGasPrice behavior they expect from Ethereum.
In practice, when your priority tip plus the base fee stays below maxFeePerGas, the receipt reports baseFee + maxPriorityFeePerGas rather than maxFeePerGas. Use the receipt’s effectiveGasPrice (not maxFeePerGas) when computing what a transaction actually paid.
SSTORE Cost
The gas cost of SSTORE (writing to contract storage) is governance-adjustable on Sei. It is currently 72,000 gas — the same on mainnet and testnet (see Divergence from Ethereum) — but treat that 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:
A Foundry forge test --gas-report --fork-url <sei rpc> report forks chain state but runs revm’s standard EVM gas schedule, so it shows SSTORE at the Ethereum cost (~22,100) rather than Sei’s ~72,000. Use it for relative profiling of your own logic; estimate the absolute storage-write cost with a live eth_estimateGas against a Sei RPC.
Summary