Layer Sports · Beta · NBA · NFL · NHL · NCAAF

Every play moves the price. See which venue moves first.

Live game markets on Kalshi and Polymarket US: the gap after fees, whose price moves first, and how long the other takes to catch up. For developers building sports trading bots.

Get an API key See the data

Read the docs →

Live spreads: NBA, NFL, NHL and NCAAF game winners on Kalshi and Polymarket US. Across Layer: 6,500+ sports markets in 60+ leagues on Kalshi, Polymarket US, Novig and more.

one play, two venues · illustrative

NBA · Miami at Utah · Q4 2:31

playUtah hits a three

kalshimoves first · yes 0.21 → 0.27

polymarket usfollows 0.2 s later · yes 0.21 → 0.26

layerKalshi led · Polymarket US followed in 0.2 s

your botdecides what to do with it

try it

curl

curl -H "Authorization: Bearer $LAYER_API_KEY" \
  "https://uselayer.sh/v0/sports/spreads?league=nba"

Free API key · 60 requests a minutesample response · one game, trimmed

json

{
  "event_id": "KXNBAGAME-26NOV10MIAUTA",
  "question": "Miami vs Utah: Miami wins",
  "status": "upcoming",
  "kalshi":        { "yes_bid": 0.74, "yes_ask": 0.75 },
  "polymarket_us": { "yes_bid": 0.75, "yes_ask": 0.76 },
  "direction": "kalshi_yes_pmus_no",
  "edge_cents": -3.09,
  "arbitrage": false,
  "contracts": 0,
  "net_dollars": 0
}

the data · live

Live spreads

Each game right now, the cheaper way round: YES on one venue, NO on the other. Closest to a profit first. Refreshes every 5 seconds.

A row is marked Arbitrage when at least one contract makes a profit after both venues' fees.

This page and the API refresh every 5 seconds. For every price change as it happens, use the live stream (Beta).

Game	Better way round	Edge	Contracts	Net	API

Who leads whom

Last 7 days: which venue's price moved first, and how long the other took to follow.

League	Moved first	Followed	Moves	Followed within 30 s	90th percentile lag	API

Market data from Kalshi (kalshi.com) and Polymarket US (polymarket.us).