Demo WebSocket API

Use the demo WebSocket endpoint to try live ticks and historical candles with the GoCharting Charting SDK. No API key or login is required.

Live demo

Chart wired to wss://gocharting.com/sdk/ws (ticks + history):

Open in CodePen | Full screen

Endpoint


wss://gocharting.com/sdk/ws

Browser clients should connect from an allowed site origin (for example gocharting.com or localhost). Tools like Postman that omit the Origin header are also supported.

After connect

The server sends a text welcome frame:


Welcome-{connection-id}

Keep the connection alive:


PING

Server reply:


PONG

You can also send PING-{token} and receive PONG-{token}.

Demo symbols

Symbol	Description
`BYBIT:FUTURE:BTCUSDT`	Bybit BTC/USDT perpetual
`BYBIT:FUTURE:ETHUSDT`	Bybit ETH/USDT perpetual

Other symbols are ignored (only allowlisted symbols appear in the ack).

Live trades are not sent until you SUBSCRIBE on that connection. UNSUBSCRIBE stops fan-out for that connection only — the demo server keeps the Bybit feeds warm in the backend regardless.

Live trades


{
  "command": "SUBSCRIBE",
  "channel": "trade",
  "payload": ["BYBIT:FUTURE:BTCUSDT", "BYBIT:FUTURE:ETHUSDT"]
}

Ack


{
  "command": "SUBSCRIBE",
  "channel": "trade",
  "payload": ["BYBIT:FUTURE:BTCUSDT", "BYBIT:FUTURE:ETHUSDT"]
}

Only supported symbols appear in the ack list.

Unsubscribe


{
  "command": "UNSUBSCRIBE",
  "channel": "trade",
  "payload": ["BYBIT:FUTURE:BTCUSDT"]
}

Trade stream (server to client)


{
  "channel": "trade",
  "payload": {
    "BYBIT:FUTURE:BTCUSDT": [
      {
        "ltp": 67542.1,
        "l_sz": 0.01,
        "side": "Buy",
        "t_ms": 1721040000123
      }
    ]
  }
}

Fields may vary slightly by feed; treat unknown fields as optional.

Historical candles (`timeseries`)

All candle traffic is JSON text frames (not binary).

Request


{
  "request_id": 1,
  "command": "timeseries",
  "payload": {
    "symbol": "BYBIT:FUTURE:BTCUSDT",
    "interval": "1m",
    "session": "RTH",
    "hint": "rows=200",
    "echo": "chart-1"
  }
}

Field	Required	Description
`symbol`	yes	Example: `BYBIT:FUTURE:BTCUSDT`
`interval`	yes	Example: `1m`, `5m`, `15m`, `1h`, `1D`
`session`	recommended	Example: `RTH`
`hint`	no	Comma-separated options, example: `rows=200`
`echo`	no	Echoed back so you can correlate chart panes
`request_id`	recommended	Echoed so you can match responses

Not supported: seconds intervals (for example 1s, 10s).

Response (one or more chunks)


{
  "command": "timeseries",
  "request_id": 1,
  "final": 1,
  "echo": "chart-1",
  "payload": {
    "criteria": {
      "symbol": "BYBIT:FUTURE:BTCUSDT",
      "interval": "1m",
      "session": "RTH"
    },
    "summary": {
      "2026-07-15": 42
    },
    "bars": {
      "2026-07-15": [
        {
          "date": "2026-07-15T10:00:00",
          "open": 67000.0,
          "high": 67120.5,
          "low": 66980.0,
          "close": 67055.2,
          "volume": 123.45
        }
      ]
    }
  }
}

`final`	Meaning
`0`	More candle chunks will follow
`1` or `2`	Done for this request

For daily (1D) bars, payload.bars may be a flat array instead of a date-to-bars map.

Errors

Most errors look like:


{
  "command": "ERROR",
  "request_id": 1,
  "message": "Human-readable message."
}

Candle errors may also include:


{
  "command": "ERROR",
  "request_id": 1,
  "in": {},
  "out": {
    "message": "Symbol BYBIT:FUTURE:ETHUSDT is not supported.",
    "dismissable": false,
    "message_type": "UNSUPPORTED_SYMBOL"
  }
}

Common messages

Situation	Message	`message_type` (if any)
Bad JSON	Invalid message.	—
Unknown command	Unsupported command.	— (plus `command_in`)
Bad subscribe payload	Invalid subscribe payload.	—
Unsupported symbol	Symbol … is not supported.	`UNSUPPORTED_SYMBOL`
Bad interval	Invalid interval.	`INVALID_INTERVAL`
Seconds interval	Seconds intervals are not supported.	`UNSUPPORTED_INTERVAL`
Empty history	No data found for ….	`NO_DATA`
Too many requests	Rate limit exceeded. Please try again later.	— (plus `remaining`)

Connection-level limits return HTTP 429 before upgrade:


Too many requests. Please try again later.

Quick start (browser)


const ws = new WebSocket("wss://gocharting.com/sdk/ws");
 
ws.onmessage = (ev) => {
  if (typeof ev.data !== "string") return;
  if (ev.data.startsWith("Welcome-") || ev.data.startsWith("PONG")) {
    console.log(ev.data);
    return;
  }
  const msg = JSON.parse(ev.data);
  console.log(msg);
};
 
ws.onopen = () => {
  ws.send("PING");
  ws.send(
    JSON.stringify({
      request_id: 1,
      command: "timeseries",
      payload: {
        symbol: "BYBIT:FUTURE:BTCUSDT",
        interval: "1m",
        session: "RTH",
        hint: "rows=200",
        echo: "demo-chart",
      },
    })
  );
};
 
setInterval(() => {
  if (ws.readyState === WebSocket.OPEN) ws.send("PING");
}, 20000);

Integrator checklist

Connect to wss://gocharting.com/sdk/ws
Expect a Welcome- frame, then send PING periodically
SUBSCRIBE the symbols you need, then listen on channel: "trade"
Fetch history with command: "timeseries" and read chunks until final is 1 or 2
Handle command: "ERROR" as a first-class response path

Demo limits

Approximate per-IP guidance (subject to change):

Up to about 5 concurrent connections
Connection / message / candle request rate limits apply
On limit: wait and retry (Retry-After on HTTP 429, or remaining on WebSocket errors)