CoW Protocol cow

CoW Protocol is a permissionless trading protocol for Ethereum and other supported networks. Its main user interface is CoW Swap, but the protocol itself is the settlement and auction layer that accepts signed trading intents and arranges their execution. The protocol was formerly known as Gnosis Protocol.

Instead of requiring a user to submit a transaction that directly calls an AMM, a user signs an intent specifying assets, amounts, limit prices and other constraints. The order is collected in an off-chain order book, then settled on-chain by a smart-contract-verified solution.

CoW Protocol uses fair combinatorial batch auctions and an open competition among independent solvers. The design combines peer-to-peer matching, available on-chain liquidity, and solver-accessible private liquidity to seek better execution while reducing users' exposure to sandwich attacks and other forms of transaction-order manipulation.

The CoW DAO supports development and governance of the protocol. COW is the ecosystem's governance token; governance venues include the forum, Snapshot and Discord.

A conventional on-chain swap exposes a user's transaction and execution route to public mempools, AMM price impact, liquidity-provider fees and MEV strategies such as sandwich attacks. Direct execution also fixes the route before execution, limiting the ability to use newly available liquidity or match another trader with the opposite need.

CoW Protocol addresses this by separating expression of a user's constraints from route construction. Solvers compete after orders are grouped into a batch, and the selected settlement must satisfy the signed limit price, quantity and signature checks. Batch-level optimization can match users directly, reduce repeated gas costs, and compare multiple liquidity sources.

The approach has trade-offs: orders are asynchronous rather than immediate transactions, and the quality of execution depends on solver competition, valid liquidity and the protocol's auction and settlement rules. Users should still verify the domain, token and order constraints they sign.

A trader signs an intent rather than an executable transaction. The intent describes the sell and buy tokens, amounts, limit price and validity constraints. Users normally approve the Vault Relayer, while the Settlement contract verifies the signed intent and enforces its conditions during execution.

The order book aggregates intents until an auction batch closes. Solvers then submit candidate solutions, including individual bids and batched bids. A fair combinatorial auction filters unfair batched bids and selects a combination that maximizes surplus for participating orders subject to computational constraints.

A winning solution may use on-chain AMMs and other liquidity, solver-held private inventory, or Coincidence of Wants (CoWs). In a simple CoW, opposite orders exchange directly without touching an AMM; batching can combine similar trades to save gas; intermediate and multidimensional CoWs can share liquidity across several assets and users.

The winning solver submits a settlement transaction. Uniform directed clearing prices make repeated trades in the same direction within a batch settle consistently, making transaction order less useful for MEV extraction. Solver bonding, allowlisting/auction rules, contract checks and post-settlement data provide the security and verification layers.