Trading data WebSocket (EQT+FNO)

Overview

This channel streams realtime account-related data: orders, buying power, and portfolio — over Socket.IO. It is a separate channel from Priceboard (see Connecting to Priceboard) and requires a valid access token.

There are two distinct paths depending on product type — use the one matching the account you’re working with:

Stocks / underlying securities: eqt
Derivatives: fno

Connection details

Setting	Underlying (EQT)	Derivatives (FNO)
Host (Production)	`https://flashapi.phs.vn`	`https://flashapi.phs.vn`
Socket.IO path	`/realtime/eqt/socket.io`	`/realtime/fno/socket.io`
Transport	`websocket`	`websocket`

Prerequisites

Before connecting, you need:

access_token — obtained from the login API (auth/gen-secret-key/underlying). It must still be valid at the time you subscribe.
sub_account_id (trading sub-account) — NOT your login username / custody code (e.g. 022Cxxxxxx). This is the actual trading sub-account number, formatted like 0301001425. Using the wrong value here causes FO20010 - Invalid sub-account errors elsewhere in the API, and prevents the realtime subscription from returning the correct account data.

Confusing the login/custody code with the trading sub-account (accountId) is the most common integration mistake for this channel. If unsure, obtain the exact accountId from the trading app or PHS operations team.

Connection steps

Call the auth API to obtain a valid token for the session.

Initialize the client

Connect to the matching host + path (eqt or fno), forcing the websocket transport.

Send the subscribe payload

After connect, emit a get event with a payload containing your sub_account_id and access_token.

Listen per channel

The server pushes data through separate events by business type — see the mapping table below.

Example code (Node.js / JavaScript — Underlying/EQT)

const io = require("socket.io-client");

const SUB_ACCOUNT = "0301001425"; // Trading sub-account — NOT your login username
const accessToken = "..."; // From the login API, never hardcoded

const socket = io("https://flashapi.phs.vn", {
  path: "/realtime/eqt/socket.io", // use /realtime/fno/socket.io for derivatives
  transports: ["websocket"],
});

socket.on("connect", () => {
  console.log("Connected:", socket.id);

  socket.emit("get", {
    data: {
      args: [`account:${SUB_ACCOUNT}`],
      op: "subscribe",
      token: accessToken,
    },
    method: "get",
    url: "/client/send",
  });
});

// Main data channels
socket.on("OM", (data) => console.log("Order Management:", data));
socket.on("CI", (data) => console.log("Cash Info:", data));
socket.on("SE", (data) => console.log("Securities Equity:", data));

socket.on("connect_error", (err) => {
  console.error("Connection error:", err.message);
});

socket.on("disconnect", (reason) => {
  console.log("Disconnected:", reason);
});

Channel mapping

Event received	Full name	Meaning	Typical UI use
`OM`	Order Management	Order status updates (matched, cancelled, amended…)	Daily order book table
`CI`	Cash Info	Buying power / cash updates	Buying power widget
`SE`	Securities Equity	Portfolio holdings updates	Portfolio / holdings table

Some older gateways may emit instrument, trade, account instead of OM/CI/SE. If you’re unsure which gateway version you’re on, register listeners for both naming sets for backward compatibility.

Response structure

Account data arrives wrapped in a common envelope. The EVENTTYPE field inside DT — not the outer Socket.IO event name — is what actually tells you whether this is OM, CI, or SE. Real example — a CI (Cash Info / buying power) event:

{
  "type": "account",
  "channel": "account",
  "label": "Account",
  "data": {
    "ACC": "0102009737",
    "DT": {
      "MSGTYPE": "R",
      "EVENTTYPE": "CI",
      "AUTOID": "0102009737",
      "ACCTNO": "0102009737",
      "AFACCTNO": "0102009737",
      "LOGTIME": "20260825-02:08:24",
      "APPLYTIME": "20260731-12:07:00",
      "PPREF": "10810",
      "PP": "10810",
      "BALANCE": "10858",
      "BALDEFOVD": "10810.264",
      "AVLWITHDRAW": "10810",
      "AVLADVANCE": "0"
    }
  }
}

Common envelope (applies to every `EVENTTYPE`)

Field	Meaning
`type` / `channel`	Internal broadcast type (`account`)
`label`	Display label (`Account`)
`data.ACC`	Trading sub-account number (accountId)
`data.DT.MSGTYPE`	Message type — `R` observed, likely Response/Realtime update
`data.DT.EVENTTYPE`	The actual data-channel code — `OM` \| `CI` \| `SE` (branch your handling on this field, not the outer Socket.IO event name)

`CI` (Cash Info — Buying Power) fields

Field	Meaning
`AUTOID`	Internal record ID — observed to match the sub-account number
`ACCTNO`	Sub-account number
`AFACCTNO`	Affiliated account number
`LOGTIME`	Log timestamp, format `YYYYMMDD-HH:MM:SS`
`APPLYTIME`	Effective timestamp for the data, same format
`PPREF`	Purchasing Power Reference — exact business meaning to be confirmed (e.g. start-of-day vs. pre-trade)
`PP`	Current Purchasing Power (buying power)
`BALANCE`	Cash balance in the account
`BALDEFOVD`	(to be confirmed) — likely balance after deducting overdue debt/advance
`AVLWITHDRAW`	Amount available to withdraw
`AVLADVANCE`	Amount available for cash advance

PPREF and BALDEFOVD are inferred from their abbreviated names and have not been officially confirmed by PHS. Verify against internal business documentation or the operations team before using them in calculations or customer-facing displays.

The DT field structure for OM (Order Management) and SE (Securities Equity) differs from CI and will be added once a corresponding real sample is available.

Troubleshooting

Symptom	Likely cause	How to check
`FO20010 - Invalid sub-account`	Used the login/custody code instead of `sub_account_id`	Confirm the `accountId` is in sub-account format (e.g. `0301001425`)
Connects fine but no `OM`/`CI`/`SE` events	Expired token, or wrong `sub_account_id` in the subscribe payload	Re-login for a fresh token; log the exact `sub_account_id` sent
Receives HTML / 301 instead of a Socket.IO handshake	Wrong path — used the Priceboard path or mistyped `eqt`/`fno`	Confirm the path matches the account type in use
`connect_error` immediately on connect	Wrong host/path, or missing `transports: ["websocket"]`	Double-check client config against the example above

Next step

For realtime market data, see Connecting to Priceboard.

API documentation

Terms and conditions

Trading data WebSocket (EQT+FNO)

Overview

Connection details

Prerequisites

Connection steps

Example code (Node.js / JavaScript — Underlying/EQT)

Channel mapping

Response structure

Common envelope (applies to every `EVENTTYPE`)

`CI` (Cash Info — Buying Power) fields

Troubleshooting

Next step

​Overview

​Connection details

​Prerequisites

​Connection steps

​Example code (Node.js / JavaScript — Underlying/EQT)

​Channel mapping

​Response structure

​Common envelope (applies to every EVENTTYPE)

​CI (Cash Info — Buying Power) fields

​Troubleshooting

​Next step

Overview

Connection details

Prerequisites

Connection steps

Example code (Node.js / JavaScript — Underlying/EQT)

Channel mapping

Response structure

Common envelope (applies to every `EVENTTYPE`)

`CI` (Cash Info — Buying Power) fields

Troubleshooting

Next step