Live Prices WebSocket

This documentation explains how to subscribe to the live price_changed feed — every price update from every marketplace we track, streamed over Socket.IO in one-second batches. It replaces polling get-aggregated-min-prices for use cases that need real-time data.

Connection

The feed runs on the standard Socket.IO protocol (client libraries exist for JavaScript, Python, Go, C#, Java and more — no custom protocol to implement):

Parameter	Value
URL	https://api.csmarketcap.com
Path	/sockets
Auth	auth: { token: <generated_jwt> } (or query: { token })

The token is the same JWT you already use for the REST and GraphQL APIs. For information on how to generate it, please refer to the Authentication Guide.

JavaScript

import { io } from "socket.io-client";

const socket = io("https://api.csmarketcap.com", {
  path: "/sockets",
  auth: { token: "<generated_jwt>" },
});

socket.on("connect", () => {
  // subscribe to everything…
  socket.emit("prices:subscribe", {}, (ack) => {
    console.log(ack); // { subscribed: "all" }
  });

  // …or to specific marketplaces only (recommended):
  socket.emit(
    "prices:subscribe",
    { markets: ["buff163", "csfloat"] },
    (ack) => console.log(ack), // { subscribed: ["buff163", "csfloat"] }
  );
});

socket.on("price_changed", ({ count, events }) => {
  for (const event of events) {
    // handle the update
  }
});

socket.on("connect_error", (err) => {
  // invalid / expired token — the reason is in err.message
  console.error(err.message);
});

Python

import socketio

sio = socketio.Client()

@sio.event
def connect():
    sio.emit("prices:subscribe", {"markets": ["buff163"]})

@sio.on("price_changed")
def on_prices(frame):
    for event in frame["events"]:
        pass  # handle the update

sio.connect(
    "https://api.csmarketcap.com",
    socketio_path="/sockets",
    auth={"token": "<generated_jwt>"},
)

Subscribing

Event	Payload	Effect
prices:subscribe	{}	Receive every marketplace
prices:subscribe	{ "markets": ["buff163", "csfloat"] }	Receive only the listed marketplaces
prices:unsubscribe	—	Stop receiving without disconnecting

Re-sending prices:subscribe replaces the previous filter. Both events accept an acknowledgement callback confirming the active subscription.

Market names match the market_name values used across the rest of the API (buff163, csfloat, skinport, waxpeer, …). The feed carries the same marketplaces as the REST endpoints — internal or inactive markets are not included. The acknowledgement always lists the markets you were actually subscribed to; unavailable names are dropped from it.

The price_changed event

Updates are batched and delivered once per second per subscription:

{
  "count": 584,
  "events": [
    {
      "market_name": "buff163",
      "game_id": 730,
      "item_name": "AK-47 | Redline (Field-Tested)",
      "price": 31250,
      "offers": 143,
      "price_locked": 29980,
      "change_datetime": "2026-07-13 16:18:34"
    }
  ]
}

Field	Description
market_name	Marketplace that reported the change
game_id	730 CS2, 570 Dota 2, 440 TF2, 252490 Rust
item_name	Full market hash name
price	Minimum price for immediately tradable items
price_locked	Minimum price for trade-locked items (may be absent)
offers	Listing count on that marketplace (may be absent)
change_datetime	UTC timestamp of the change

Usage Notes

• Price values are provided in cents (divide by 1000 to get dollar value) — same convention as the REST API
• The unfiltered stream averages ~650 events per second with bursts far above that; subscribe per-market unless you truly need everything
• One price_changed frame per second per subscription — an empty second produces no frame
• Reconnection and transport fallback (WebSocket → HTTP long-polling) are handled by the Socket.IO client automatically
• Authentication failures surface as connect_error with the reason (Invalid token, Your subscription has expired…); token lifetime is unchanged, so mint a new token and reconnect when it expires
• All games flow through one subscription — filter by game_id client-side if you only need one