Kalshi Sports Market Data API

Quick Start

No API key needed. Just start making requests:

Copy# Get all NBA game lines in one call
curl http://localhost:4000/api/prices/summary?sport=NBA

# Get live contract prices (ultra-slim, lowest latency)
curl http://localhost:4000/api/prices?sport=NBA&side=YES

# Search for a team
curl http://localhost:4000/api/search?q=Boston

# Full event details with all markets and contracts
curl http://localhost:4000/api/events?sport=NBA&limit=5

Data Model

Each sport has a simple hierarchy:

Sport (NBA, MLB, NFL, NHL)
  └── Event (a game — e.g. "Brooklyn at Toronto")
        └── Market (a prediction — e.g. "Winner?", one per team)
              └── Contract (YES/NO side — price is 0.00–1.00)

Prices are in dollar terms. A YES price of $0.60 = 60% implied probability.
Each game typically has 2 markets × 2 contracts = 4 contracts total.

Response Format

All list endpoints return a standardized envelope:

{
  "data": [ ... ],           // Array of results
  "meta": {
    "count": 15,            // Items in this response
    "total": 86,            // Total matching (for pagination)
    "cached": false,        // true if served from Redis cache
    "took_ms": 3.2          // Server processing time
  }
}

Response Headers

Errors

All errors follow a consistent shape:

{
  "error": {
    "code": "NOT_FOUND",
    "message": "Market 'abc' not found"
  },
  "meta": { "cached": false, "took_ms": 1.2 }
}

Endpoints

WebSocket API

Connect to ws://localhost:4000/ws/v1 for real-time streaming.

Channels

Actions

// Subscribe to NBA
{"action": "subscribe", "channel": "sport:NBA"}

// Unsubscribe
{"action": "unsubscribe", "channel": "sport:NBA"}

// Request a full snapshot
{"action": "snapshot", "channel": "sport:NBA"}

// Switch to delta mode (only changed fields)
{"action": "set_mode", "mode": "delta"}

// Heartbeat
{"action": "ping"}

Message Types