// the find
valorem-labs-inc/quay
An open source, high performance limit order book for the Seaport smart contracts. Implemented in Rust using ethers-rs, this offers a turnkey option for digital asset marketplaces.
Quay is a Rust backend for order book management on top of OpenSea's Seaport smart contracts, targeting NFT/ERC-721 marketplaces that want to build signature-based trading without writing their own off-chain infrastructure. It handles offer/listing storage in Postgres, SIWE authentication, and on-chain validation via ethers-rs bindings.
The tech stack is well-chosen: actix-web, sqlx with compile-time checked queries, and tracing instrumentation throughout — this is how a production Rust web service should be structured. SIWE (EIP-4361) is the right auth mechanism for this use case and it's implemented as first-class, not bolted on. The separation of indexer and API into distinct binaries is correct; most projects conflate these and regret it. Proto definitions for RFQ suggest they were building toward a gRPC streaming interface for quote requests, which is the right call for low-latency order flow.
Last push was June 2023 — ethers-rs has since been superseded by alloy-rs, so the core dependency is effectively abandoned and this codebase is on a dead branch of the Rust Ethereum ecosystem. The order book logic itself is thin: there's no visible price-time priority queue, no order matching engine, and no cancellation handling in the directory tree, which is most of what 'limit order book' implies. Error handling on routes returns a bare 500 on any failure (`is_err()` branch), with no structured error types visible — debugging production issues will be painful. Redis is used only for session storage, which is fine, but the README hints at gossip (`src/bin/gossip.rs`) with zero documentation on what that binary actually does.