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Documentation Index

Fetch the complete documentation index at: https://docs.delphimarkets.com/llms.txt

Use this file to discover all available pages before exploring further.

The Delphi Markets WebSocket API provides real-time streaming for price updates, orderbook snapshots, and trade executions across all supported exchanges.

Supported streams

Kalshi

Subscribe using klsi_id. Prices, orderbook (101-level depth), and trades.

Polymarket

Subscribe using condition_id. Prices, orderbook, and trades.

Predict.fun

Subscribe using market_id. Prices, orderbook, and trades.

Limitless

Subscribe using market_id. Prices, orderbook, and trades.

Gemini

Subscribe using market_id. Prices, orderbook, and trades.

Manifold

Subscribe using market_id. Prices, orderbook, and trades.

Opinion

Subscribe using market_id. Prices, orderbook, and trades.

ForecastEx

Subscribe using market_id. Prices and trades (no orderbook).

PredictIt

Subscribe using market_id. Prices only.

Parlays

Subscribe using market_ids. RFQ events and MVE trades. Requires Pro+ plan.

How it works

  1. Connect to the WebSocket endpoint for your exchange
  2. Subscribe by sending a JSON message with market IDs and message types
  3. Receive real-time updates as JSON messages
  4. Unsubscribe or disconnect when done

Common connection details

All WebSocket streams share these properties:
PropertyValue
ProtocolWebSocket (wss://)
AuthenticationAPI key via api_key query parameter
KeepalivePing every 54 seconds
Timeout60 seconds without pong
Default message typesPrices and orderbook

Subscription key reference

ExchangeEndpointSubscription keyMessage types
Kalshi/ws/kalshiklsi_idsprices, orderbook, trades
Polymarket/ws/polycondition_idsprices, orderbook, trades
Predict.fun/ws/pfunmarket_idsprices, orderbook, trades
Limitless/ws/limitlessmarket_idsprices, orderbook, trades
Gemini/ws/gemimarket_idsprices, orderbook, trades
Manifold/ws/manimarket_idsprices, orderbook, trades
Opinion/ws/opnmmarket_idsprices, orderbook, trades
ForecastEx/ws/fexmarket_idsprices, trades
PredictIt/ws/prdimarket_idsprices
Parlays/ws/parlaysmarket_idsrfq, mve_trades

Quick start

const ws = new WebSocket("wss://api.delphimarkets.com/ws/kalshi?api_key=YOUR_API_KEY");

ws.onopen = () => {
  ws.send(JSON.stringify({
    action: "subscribe",
    klsi_ids: ["KXBTCD-25FEB14-B55000"],
    message_types: ["prices", "orderbook", "trades"]
  }));
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  console.log(data);
};
See the individual stream pages for complete subscription fields, message schemas, and examples.