Show HN: A free dataset, Polymarket's 5-minute crypto markets, second-by-second (opens in new tab)

A free dataset of Polymarket's 5-minute crypto up/down markets — BTC, ETH, SOL, XRP, DOGE, HYPE, BNB — recorded second by second, ~89k markets and ~26.8M order-book observations, March–May 2026. Full data dictionary, coverage, provenance and limitations.