Polymarket Vice President of DeFi Engineering Josh announced that Nex, the platform's new trading system rewritten in Rust, has opened for sandbox testing. Over the past week, the system has mirrored production orders in shadow mode to verify latency, load stability, and matching accuracy ahead of its official launch. Internal test data shows P99 order latency dropped from 1.55 seconds on the existing central limit order book (CLOB) to 3.76 milliseconds under Nex, though this metric does not represent end-to-end latency. The team plans four weeks of shadow testing, with a full launch expected in mid-December if results hold. WebSocket improvements may roll out earlier than the main system launch.