Scanna

https://api.scanna.xyz/leaderboard

Top Polymarket traders by realised PnL or volume. Normally a 5-minute shared cache, but if upstream fails we serve the last good copy for UP TO 24 HOURS, still as a 200, signalled only by the X-Data-Freshness header. 503 only when nothing is cached at all. Upstream rows are sparse: proxy_wallet is the only guaranteed field; pnl and volume can be null and trades can be absent. limit is truncated locally before enrichment, so it bounds work. Empty bills.