Polymarket TWAP60 vs Kalshi: Why Settlement Design Decides Your Bot (Series 1/4)

GitHub: https://github.com/abrownfox0/abrownfox001-twap60-prediction-trigger-system YouTube walkthrough: https://www.youtube.com/watch?v=XzhugRL6BV4 This is a new 4-part series comparing the two venues that actually matter for short-horizon BTC direction: Part 1 — Settlement design: Polymarket TWAP60 vs Kalshi 60s average (this post) Part 2 — Product shape: 5-minute specialist vs 15-minute regulated stack Part 3 — What a directional bot must change when crossing venues Part 4 — Where edge survives, and where it dies Live profile: @abrownfox001 The Real Split Is Not “On-Chain vs Regulated” People compare Polymarket and Kalshi as if the important difference is KYC, geography, or chain vs centralized matching. For a short-horizon BTC bot, those matter later. The first difference is simpler: What exact number decides Up vs Down? If you get that wrong, every signal, backtest, and scratch rule is solving the wrong problem. Two Venues, Two Official Averages Both platforms moved away from “whatever the last print was.” Both now settle short BTC contracts on a one-minute average . They do not use the same average. Polymarket crypto Up/Down Kalshi BTC short contracts Shortest liquid product 5-minute Up/Down 15-minute Up/Down ( KXBTC15M ) Settlement idea Time-weighted average 60-second simple average Official source Chainlink TWAP CF Benchmarks Real-Time Index (BRTI family) Window 60 seconds for current 5m / 15m / 4h crypto Final 60 seconds before close , sampled ~1s Open reference Matching TWAP at slot start Strike / floor set by the contract Feed path for bots Polymarket RTDS or Chainlink Data Streams Kalshi market fields + CF Benchmarks index Market structure On-chain CLOB Centralized CFTC-regulated exchange Same word — “60-second average.” Different index. Different sampling. Different product clock. Why Both Platforms Converged on 60 Seconds Snapshot settlement created the same failure mode everywhere: A brief push into one venue’s book A wick at the exact close Retail on