Sports prediction market data API — NBA, NFL, EPL, FIFA World Cup

What is captured

Each Polymarket sports market has two tokens — UP (one team wins) and DOWN (the other) — and each token has its own orderbook in USDC probabilities (0.01–0.99). For every event from the upstream Polymarket WebSocket, we apply the delta in memory, derive best bid/ask, mid, spread, depth at the top 5 levels, and persist a full snapshot if the top-of-book changed. Every snapshot carries:

• Full bids and asks arrays as Array(Tuple(price, size))
• best_bid, best_ask, mid, spread
• Cumulative depth at the top 5 price levels per side
• Monotonic sequence_number (gap detection)
• event_timestamp from Polymarket and capture_timestamp from our pipeline
• Token side (UP / DOWN) and the parent condition_id

Pull live NBA or FIFA World Cup orderbooks

# 1. List active NBA markets (swap subcategory=FIFA for World Cup matches)
curl -s "https://api.resolvedmarkets.com/v1/markets/live?category=sports&subcategory=NBA" \
  -H "X-API-Key: rm_your_key" | jq '.markets[] | {slug, condition_id, question}'

# 2. Pull live orderbook for one market
curl -s "https://api.resolvedmarkets.com/v1/markets/<condition_id>/orderbook" \
  -H "X-API-Key: rm_your_key" | jq '.up.bids[0:5]'

# 3. Pull last 4 hours of snapshots for time-series analysis
curl -s "https://api.resolvedmarkets.com/v1/markets/<condition_id>/snapshots?limit=500" \
  -H "X-API-Key: rm_your_key" | jq '.snapshots[0]'

FIFA World Cup matches are three-way moneylines — Polymarket groups the home-win, away-win, and draw outcomes under one event (e.g. "Argentina vs. Austria"), and each outcome is its own Yes/No market with an independent orderbook. List them with ?category=sports&subcategory=FIFA; every match is tracked automatically from the moment Polymarket lists it through resolution.

Use cases

• In-game probability research. Reconstruct minute-by-minute implied probabilities through the final quarter of close games and benchmark against win-probability models.
• Spread compression studies. Measure how spreads tighten as resolution approaches — Polymarket sports markets often see sub-cent spreads in the last minutes of play.
• World Cup three-way pricing. Track how home / away / draw probabilities re-price across a 2026 FIFA World Cup match — into kickoff, after goals, and through stoppage time — and check whether the three outcomes sum cleanly to 1.0.
• Cross-market arbitrage signals. Compare Polymarket discrete-outcome prices against centralized sportsbooks, in-play odds feeds, or DraftKings markets where regulation allows.
• AI agent reporting. Wire the MCP server into a Claude or ChatGPT agent and ask "what was the implied probability of the Lakers winning at the start of the 4th quarter on game X?"