// the find
Ellipsis-Labs/phoenix-v1
On-chain order book that atomically settles trades
Phoenix is a Solana program implementing a fully on-chain central limit order book that settles atomically without a crank — no off-chain keeper required. It's for DeFi protocols and market makers who need a trustless, composable order book primitive rather than an AMM. This is v1 (now called Phoenix Legacy), meaning there's a newer version in development.
The crankless design is the real differentiator — atomic settlement means no MEV exposure from delayed crank execution that plagues other on-chain order books. The FIFO matching engine in `src/state/markets/fifo.rs` is a proper price-time priority queue, not a bonding curve approximation. Two independent audits (OtterSec and MadShield) with reports in-repo, plus a verifiable build hash you can check against the deployed program ID — unusually high trust bar for a DeFi protocol. The quantities abstraction in `src/quantities.rs` handles fixed-point arithmetic carefully, which is where most on-chain exchange implementations quietly break.
The README is essentially a pointer to GitBook, so if that documentation goes down you're left reading Rust with no context. Seat management adds friction — traders need a seat allocated before they can place orders, which is a non-obvious onboarding hurdle not explained anywhere in the repo itself. The 'Legacy' designation is a real concern: if Ellipsis is shipping a v2, building on v1 now means you're on a deprecated protocol with no migration path documented. 275 stars and a v1 tag on a financial primitive is thin community signal for something handling real money.