orthogonal-sh/prediction-market-odds

Prediction Market Odds

Get current odds, prices, and market data from prediction markets like Polymarket and Kalshi.

When to Use

• User asks about prediction market odds
• User wants to know probability of an event
• User asks "what are the odds of [event]?"
• Research on market sentiment
• Election or event probability checks

How It Works

Uses the Dome API to aggregate prediction market data from Polymarket and Kalshi.

Usage

Get Polymarket Markets

orth run dome /polymarket/markets -q 'status=open'

<details> <summary>curl equivalent</summary>

curl -X POST "https://api.orth.sh/v1/run" \
  -H "Authorization: Bearer $ORTHOGONAL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"api":"dome","path":"/polymarket/markets"}'

</details>

Search Markets

orth run dome /polymarket/markets -q 'search=election' -q 'status=open'

Get Kalshi Markets

orth run dome /kalshi/markets

Get Polymarket Activity

orth run dome /polymarket/activity

Get Market Orders

orth run dome /polymarket/orders

Get Sports Markets

orth run dome /matching-markets/sports

Get Specific Sport Markets

orth run dome /matching-markets/sports/nba

Supported Sports

• nba
• nfl
• mlb
• nhl
• soccer
• tennis

Response

Markets Response (/polymarket/markets, /kalshi/markets)

Returns markets array:

• title (string) - Market question (e.g., "Will Trump nationalize elections?")
• market_slug (string) - URL-friendly identifier
• condition_id (string) - Blockchain condition ID
• start_time / end_time (integer) - Unix timestamps
• completed_time (integer|null) - Null if still open
• tags (array) - Category tags (e.g., ["politics", "us election"])
• volume_1_week / volume_1_month / volume_1_year / volume_total (number) - Trading volume in USD
• side_a / side_b (object) - id and label (typically "Yes"/"No")
• winning_side (object|null) - Null if unresolved
• image (string) - Market thumbnail URL

Activity Response (/polymarket/activity)

Returns activities array:

• title (string) - Market title
• market_slug (string) - Market identifier
• side (string) - Trade side: BUY, SELL, or MERGE
• shares (integer) - Raw share amount
• shares_normalized (number) - Human-readable share amount
• price (number) - Trade price (0-1, represents probability)
• timestamp (integer) - Unix timestamp of the trade
• user (string) - Wallet address of the trader
• tx_hash (string) - Blockchain transaction hash

Examples

User: "What are the odds on Polymarket right now?"

orth run dome /polymarket/markets -q 'status=open'

User: "Show me Kalshi prediction markets"

orth run dome /kalshi/markets

User: "What's happening in prediction markets?"

orth run dome /polymarket/activity

User: "Any sports betting markets?"

orth run dome /matching-markets/sports

Understanding Odds

• Prices are shown as decimals (0.65 = 65% probability)
• "Yes" price = probability market thinks event will happen
• Higher volume = more confidence/liquidity
• Prices change based on trading activity

Error Handling

• 400 - search requires status parameter (open or closed) — always include both
• 401 - Invalid API key
• 429 - Rate limit — wait and retry
• Empty markets array means no markets match the search term
• Activity endpoint returns recent trades globally — no filters required

Tips

• Check multiple markets for the same event
• Volume indicates market confidence
• Recent activity shows sentiment shifts
• Polymarket focuses on politics/world events, Kalshi on finance/weather