Polymarket trading API fails again, halts orders
Polymarket's central limit order book (CLOB) trading API suffered a major outage on August 31, causing delayed responses on unfilled order reads. The platform suspended trading during the incident and canceled orders amid the disruption. VP Engineering Josh Stevens said the company will rebuild the CLOB from scratch in Rust, targeting 200,000 orders per second and 10–20x faster p99 latency than current infrastructure.
Polymarket is rebuilding its entire CLOB stack in Rust after repeated outages, a direct admission that the current system cannot handle the load. VP Engineering Josh Stevens set a target of 200,000 orders per second, a benchmark that reveals how far behind the existing infrastructure has fallen. Each failure hits algorithmic traders hardest, and those market makers already have cleaner alternatives in Kalshi and Novig.
The CFTC does not publish uptime scores, but operational risk is part of its oversight remit. Polymarket's push into U.S. parlays and institutional API access depends on proving reliability first. Competitors with stable stacks will capture the institutional flow while Polymarket is still recompiling.