Sui Cuts the Gas Charge for Calling Move Packages by 99% in Protocol Upgrade

Sui mainnet moved to protocol version 139 at the start of epoch 1289, at 5:05 PM PT on October 22 (00:05 UTC on October 23). The upgrade cuts the size-based read charge that transactions pay for the Move packages they call by about 99%.

What changes

Until now, every transaction paid a read charge on the full size of each non-system Move package it called, at 15 internal gas units per byte. The charge applied on every transaction, even though validators cache packages. Under protocol 139, package inputs are charged 154 internal gas units per kibibyte (KiB), or about 0.15 per byte. That is roughly 1% of the old rate. The charge for reading regular objects stays the same.

The change was written by Mysten Labs engineer Mark Logan and ships in Sui v1.82.3, which Mysten Labs released for mainnet on October 21. Onchain data confirms the new setting is active.

How big the savings are

The old charge fell hardest on large applications. According to the Mysten Labs code change, a single call into a 100 KB package paid about 1,500 gas units before any code ran, and package bytes made up about 11% of computation fees in a sample of mainnet transactions.

A draft Sui Improvement Proposal (SIP) Logan filed in September, titled "Reduce Gas Costs for Onchain Order Books", walks through a real mainnet transaction that canceled and placed orders on an onchain perpetuals exchange. Reading its three packages accounted for 92.8% of its computation gas. Replaying that transaction at the new rate, the code change shows computation falling from 1,702 gas units to 137.

Why it matters

The SIP's stated goal is to make onchain order books much cheaper to run, because market makers requote constantly and small fees add up. It argues that the package charge does not reflect a real cost for validators, and that it made it pointless in most cases for developers to optimize the gas their code uses.

The same proposal also covered the non-refundable storage fee, which Sui keeps each time a transaction rewrites or deletes an object. That fee was already cut from 1% to 0.01% of the storage rebate on mainnet in protocol version 138. With both changes now live, trading apps that call large packages and rewrite shared objects on every order, such as order books and perpetuals exchanges, stand to benefit most.