Quickstart

import { createStreamClient } from "@parlayx/sdk/stream";

const stream = createStreamClient({
  keyId: process.env.PARLAYX_KEY_ID!,
  privateKeyHex: process.env.PARLAYX_PRIVATE_KEY_HEX!,
});

/* A local book we keep in sync from snapshot + delta frames. */
const book = { bids: new Map<number, number>(), asks: new Map<number, number>() };

/* The full book state. Arrives once per subscription, before any deltas. */
stream.on("snapshot", (frame) => {
  book.bids = new Map(frame.bids.map((l) => [l.price, l.size]));
  book.asks = new Map(frame.asks.map((l) => [l.price, l.size]));
  console.log(`snapshot seq=${frame.seq}: ${book.bids.size} bids / ${book.asks.size} asks`);
});

/* Incremental changes. size 0 deletes the level; anything else sets it. */
stream.on("delta", (frame) => {
  for (const change of frame.changes) {
    const side = change.side === "bid" ? book.bids : book.asks;
    if (change.size === 0) side.delete(change.price);
    else side.set(change.price, change.size);
  }
});

/* Subscribe. The `book` channel is the default, so `channels` is optional. */
stream.subscribe([{ venue: "polymarket", tokenId: "71045620195867637" }]);

let subscriptionId: string | undefined;

stream.on("subscribed", (frame) => {
  subscriptionId = frame.subscriptionId;
  console.log(`subscribed ${frame.subscriptionId} (${frame.channel})`);
});

/* later... */
if (subscriptionId) stream.unsubscribe([subscriptionId]);
stream.close(); /* closes the socket and stops reconnecting */

import WebSocket from "ws";

const stream = createStreamClient({
  keyId: process.env.PARLAYX_KEY_ID!,
  privateKeyHex: process.env.PARLAYX_PRIVATE_KEY_HEX!,
  baseUrl: "wss://wss.parlayx.com", /* override the origin (e.g. staging); path is always /v1/orderbook */
  WebSocket, /* inject a WebSocket implementation for tests or Node.js older than 22 */
});