/okx-dex-market

Onchain OS DEX Market — WebSocket Protocol Reference

This document is for developers and agents who want to connect directly to the Onchain OS DEX WebSocket and subscribe to real-time market data (prices, candlesticks).

Endpoint

wss://wsdex.okx.com/ws/v6/dex

Uses TLS. Connect with any standard WebSocket client that supports TLS.

Authentication

The Onchain OS DEX WebSocket uses HMAC-SHA256 API key authentication, which is the same scheme as the OKX REST API. Full documentation: 👉 https://web3.okx.com/onchainos/dev-docs/market/websocket-login

Credentials

Obtain your API Key, Secret Key, and Passphrase from the OKX Developer Portal.

Security: Never hardcode credentials in source code. Use environment variables or a .env file. Ensure .env is listed in .gitignore — never commit it to version control.

Login Message

After connecting, send a login message before subscribing:

{
  "op": "login",
  "args": [{
    "apiKey":     "<your_api_key>",
    "passphrase": "<your_passphrase>",
    "timestamp":  "<unix_seconds_as_string>",
    "sign":       "<base64_hmac_signature>"
  }]
}

Signature algorithm:

prehash = timestamp + "GET/users/self/verify"
sign    = Base64( HMAC-SHA256(secret_key, prehash) )

• timestamp: current Unix time in seconds (string)
• secret_key: your Secret Key (used as the HMAC key)
• prehash: string concatenation of timestamp and the literal GET/users/self/verify

Example (Python):

import hmac, hashlib, base64, time

def make_sign(secret_key: str) -> tuple[str, str]:
    ts = str(int(time.time()))
    prehash = ts + "GET/users/self/verify"
    sig = base64.b64encode(
        hmac.new(secret_key.encode(), prehash.encode(), hashlib.sha256).digest()
    ).decode()
    return ts, sig

ts, sign = make_sign("YOUR_SECRET_KEY")
login_msg = {
    "op": "login",
    "args": [{"apiKey": "YOUR_API_KEY", "passphrase": "YOUR_PASSPHRASE",
              "timestamp": ts, "sign": sign}]
}

Example (JavaScript/Node):

const crypto = require('crypto');

function makeSign(secretKey) {
  const ts = String(Math.floor(Date.now() / 1000));
  const prehash = ts + 'GET/users/self/verify';
  const sign = crypto.createHmac('sha256', secretKey)
    .update(prehash).digest('base64');
  return { ts, sign };
}

Login ACK

The server responds with:

{ "event": "login", "code": "0", "msg": "" }

code = "0" means success. Any other code means failure — check msg for details. Wait for this ACK before sending subscribe messages. Recommended timeout: 10 seconds.

Push Message Envelope

Every push message from the server uses the same envelope structure:

{ "arg": { "channel": "...", ... }, "data": [{ ... }] }

• arg: echoes back the subscription parameters (channel, chainIndex, etc.)
• data: array containing the actual push payload — the fields described per channel below

The "Push Data Fields" tables below describe the contents of each object inside the data array, not the top-level message.

Channels

price — Token Price

Retrieve the latest price of a token. Data is pushed whenever there is an update.

Subscribe arg:

{ "channel": "price", "chainIndex": "1", "tokenContractAddress": "0x382bb..." }

Subscribe Parameters

Push Data Fields

Push Example

{
  "arg": {
    "channel": "price",
    "chainIndex": "1",
    "tokenContractAddress": "0x382bb369d343125bfb2117af9c149795c6c65c50"
  },
  "data": [{
    "time": "1716892020000",
    "price": "26.458143090226812"
  }]
}

dex-token-candle{period} — Candlestick

Retrieve candlestick (K-line) data for a token. Maximum push frequency: once per second.

Available Channel Names

Subscribe arg:

{ "channel": "dex-token-candle1m", "chainIndex": "1", "tokenContractAddress": "0x382bb..." }

Subscribe Parameters

Push Data Fields

Push Example

{
  "arg": {
    "channel": "dex-token-candle1m",
    "chainIndex": "1",
    "tokenContractAddress": "0x382bb369d343125bfb2117af9c149795c6c65c50"
  },
  "data": [{
    "ts": "1716892020000",
    "o": "26.1",
    "h": "26.8",
    "l": "25.9",
    "c": "26.5",
    "vol": "123456.78",
    "volUsd": "3267890.12",
    "confirm": "0"
  }]
}

Subscribe Message

Send a single subscribe message containing all channel args:

{
  "op": "subscribe",
  "args": [
    { "channel": "price", "chainIndex": "1", "tokenContractAddress": "0xabc..." },
    { "channel": "dex-token-candle1m", "chainIndex": "1", "tokenContractAddress": "0xabc..." }
  ]
}

Subscribe ACK

The server sends one ACK per subscription arg:

{ "event": "subscribe", "arg": { "channel": "price", "chainIndex": "1", "tokenContractAddress": "0xabc..." }, "connId": "abc123" }

Wait for N ACKs (one per arg) before considering the session active. If any arg fails, you receive:

{ "event": "error", "code": "...", "msg": "..." }

Unsubscribe Message

To cancel one or more channel subscriptions without disconnecting:

{
  "op": "unsubscribe",
  "args": [{ "channel": "price", "chainIndex": "1", "tokenContractAddress": "0xabc..." }]
}

The args array uses the same object format as subscribe.

Unsubscribe ACK

On success:

{
  "event": "unsubscribe",
  "arg": { "channel": "price", "chainIndex": "1", "tokenContractAddress": "0x382bb369d343125bfb2117af9c149795c6c65c50" },
  "connId": "d0b44253"
}

On failure:

{ "event": "error", "code": "...", "msg": "..." }

Heartbeat

Send "ping" as a plain text frame every 25 seconds. The server responds with "pong". If no pong is received within 25 seconds, reconnect.

client → "ping"
server → "pong"

Connection Lifecycle

1. connect (TLS WebSocket)
2. send login message
3. wait for login ACK  ← timeout 10s
4. send subscribe message
5. wait for N subscribe ACKs  ← timeout 10s
6. receive push data frames
7. send ping every 25s, expect pong
8. on disconnect: reconnect and repeat from step 1

Reconnection Strategy

The server may disconnect clients during maintenance or network issues. Recommended reconnect policy:

• Max attempts: 20
• Delay between attempts: 3 seconds
• On exhaustion: surface error to the user

After reconnecting, re-send the full login + subscribe sequence.