Shio

Historical documentation for Shio, the MEV Protocol on Sui

Shio wound down and permanently shut down on 12 May 2026. Proud to have led MEV infra on Sui. Until we meet again.

Overview

In the rapidly evolving world of DeFi, every trade that users execute can be influenced by hidden forces like Maximal Extractable Value (MEV), which can quietly divert value from transactions. Shio was designed to protect users and protocols from losing value to MEV strategies, such as Loss-versus-Rebalancing and Sandwich attacks, while ensuring that market efficiencies benefit users directly.

Prior to Shio's launch, MEV searchers were active on Sui, capturing significant value away from the ecosystem. Data from October'24 showed that MEV arbitrage profits averaged around $18,000 per day, amounting to over $6 million per year extracted from the Sui community.

As the first MEV protection solution in the Sui ecosystem, Shio was dedicated to capturing this value and redirecting it back to the community.

In pursuit of this mission, Shio partnered with leading DeFi projects on the Sui blockchain to enhance the DeFi experience for all users.

What is MEV?

Maximal Extractable Value (MEV) refers to the profit that can be captured by strategically ordering, censoring, or inserting transactions within a blockchain. Common MEV strategies include arbitrage, sandwiching, and liquidation.

About Shio

Our focus was to:

• Protect against MEV within the Sui ecosystem.

• Illuminate the MEV "dark forest" on Sui, democratizing access for a broader set of searchers.

• Expose dishonest behaviors in the ecosystem and improve transparency.

Historical Benefits of Shio

• Boosted DeFi Market Efficiency: Shio protected traders and liquidity providers by redistributing value back to the Sui ecosystem.

• Fair and Transparent MEV Access: Shio democratized MEV, providing opportunities for a broader pool of searchers, rather than concentrating profits among searchers with infrastructure advantages (where winners are not always the ones that produce the best rebate to the ecosystem).

• Cheating Prevention: Shio added visibility to prevent dishonest activities, such as validators or RPC providers sandwiching user transactions.

Sui Protocol Change (SIP-19)

The Shio team proposed and implemented SIP-19, which introduces "soft bundle primitives". These primitives allow transactions to be grouped and ordered without directly interfering with the Sui consensus mechanism. SIP-19 has now been deployed across the Sui ecosystem.

Sui Protocol Change (SIP-45)

The Shio team proposed and implemented SIP-45, which enables effective 'prioritized transaction submission' based on gas price. This allows users to land a transaction earlier by setting a higher gas, while normal transaction gas price stays untouched. This unlocks opportunities for users while generating more gas revenue to benefit the ecosystem. SIP-45 has now been approved and merged.