Polymarket opens Nex sandbox with 100,000 commands per second target

Polymarket’s vice president of engineering for DeFi, Josh Stevens, announced on X on Nov. 13 that the company has opened sandbox testing for Nex, a trading system rewritten in Rust, with a conditional mid-December launch planned. The exchange’s current central limit order book handles 10,000 commands per second under steady load, while Nex is designed to handle 100,000, according to Crypto.news.

The announcement, first reported by Crypto.news, said Nex had spent the previous week running alongside the existing exchange in shadow mode, mirroring every production order so engineers could compare response times, stability under load, and matching accuracy.

Performance gains and engineering overhaul

The performance figures Stevens published show significant improvements across several metrics. At the 99th percentile, canceling orders dropped from 627.92 milliseconds to 3.20 milliseconds, while canceling market orders fell from 810.16 milliseconds to 5.14 milliseconds. At p95, order placement improved from 341.84 milliseconds to 1.59 milliseconds.

Stevens described the old CLOB as having race conditions and inconsistent behavior, saying Nex was designed to produce consistent results and remove those problems. The team began the rewrite in August after concluding the existing system needed to be rebuilt from scratch.

Startup time has also fallen from five minutes to 15 seconds, according to the announcement. The rewritten Rust WebSocket service, which delivers order-book changes, prices and fills, recorded p99 write latency of 0.099 milliseconds against 44.5 to 88.1 milliseconds previously. Stevens noted that delayed feeds can leave traders quoting against old prices, and WebSocket improvements can be deployed separately from the exchange, so the team may release them before Nex goes live.

Shadow testing and compatibility

The sandbox lets participants compare Nex with the current CLOB and submit feedback before deployment. Stevens said the team plans four weeks of shadow operation before deciding whether to deploy it in mid-December. The exchange has not switched over to Nex.

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According to PANews, the shadow-mode testing over the past week verified latency, load stability and matching accuracy, and the system has not yet gone live officially. The internal test data disclosed shows that P99 order latency has fallen from 1.55 seconds on the existing CLOB to 3.76 milliseconds, though this metric is not end-to-end latency.

Stevens said the figures published are internal exchange timings, not end-to-end performance, and that those measurements would follow. The distinction means the published numbers do not measure the full journey from a trader submitting an instruction to receiving the result.

Why it matters

Polymarket’s existing CLOB has been a bottleneck for the platform’s growth, and the Nex upgrade could significantly increase capacity for traders and market makers. The improvements in order placement and cancellation speeds may reduce slippage and improve the overall trading experience. The work follows Polymarket’s in-house indexing overhaul, which surfaced some blockchain events up to 14 blocks, or roughly 28 seconds, faster. Earlier this year, Polymarket rolled out a Protocol V2 smart contract overhaul, indicating a broader effort to upgrade its infrastructure.

What to watch

The key next step is the completion of the four-week shadow testing period and Polymarket’s decision on whether to deploy Nex in mid-December. The team may also release WebSocket improvements before Nex goes live, depending on testing results.

Sources: crypto.news, PANews