Subscribe Feed

This document details how to subscribe to the market feed on the Firstock Websockets.

Overview

The Subscribe Feed API enables you to initiate a persistent WebSocket connection to Firstock’s real-time market data stream. Through this connection, you can subscribe to price feeds (LTP, and more) for multiple instruments simultaneously, receiving bundled updates in a single message

Body

Request

Multiple Token

{"action":"subscribe","tokens":"BSE:500470|NSE:26000"}

action = Type of request; subscribe indicates a live subscription to market data

tokens = Parameters for subscription. In Multiple Token, we can send multiple tokens in single request.

Single Token

{"action":"subscribe","tokens":"NSE:2885"}

action = Type of request; subscribe indicates a live subscription to market data

tokens = Parameters for subscription. In Single Token, we can send only one tokens in single request.

Example Usage

from firstock import Firstock, FirstockWebSocket
import time

def subscribe_feed_data(data):
    print(data)

user_id = 'YOUR_USER_ID'

model = FirstockWebSocket(
    subscribe_feed_data=subscribe_feed_data,
    tokens=["NSE:26000"]
)

conn, err = Firstock.initialize_websockets(user_id, model)
print("Error:", err)

if conn:
    err = Firstock.subscribe(conn, ["BSE:1"])
    print("Subscribe Error:", err)

time.sleep(25)

err = Firstock.unsubscribe(conn, ["NSE:26000", "BSE:1"])
print("Unsubscribe Error:", err)

time.sleep(5)

close_err = Firstock.close_websocket(conn)
print("Close Error:", close_err)

const { Firstock, FirstockWebSocket } = require("firstock");

// Define callback method 
function subscribeFeedData(data) {
    console.log(data);
}

const userId = 'YOUR_USER_ID';
const model = new FirstockWebSocket({
    subscribe_feed_data: subscribeFeedData,
    tokens: ["NSE:26000"]
});

async function main() {
    // Create the Firstock instance
    const firstock = new Firstock();
    
    const [conn, err] = await firstock.initializeWebsockets(userId, model);
    console.log("Error:", err);
    
    if (conn) {
        const subscribeErr = await firstock.subscribe(conn, ["BSE:1"]);
        console.log("Subscribe Error:", subscribeErr);
    }
    
    await new Promise(resolve => setTimeout(resolve, 25000));
    
    // Unsubscribe
    const unsubErr = await firstock.unsubscribe(conn, ["NSE:26000", "BSE:1"]);
    console.log("Unsubscribe Error:", unsubErr);
    
    await new Promise(resolve => setTimeout(resolve, 5000));
    
    // Close WebSocket connection
    const closeErr = await firstock.closeWebsocket(conn);
    console.log("Close Error:", closeErr);
}

main();

import (
	"github.com/the-firstock/firstock-developer-sdk-golang/Firstock"
)

//Establishing WebSocket Connection
var conn1 *websocket.Conn

func webSocketConnection1(conn *websocket.Conn) {
  if conn != nil {
    conn1 = conn
  }
}

//CallBack method
func subscribeFeedData(data Firstock.SubscribeFeedModel) {
  fmt.Println(data)
}

model := Firstock.WebSocketModel{
    SubscribeFeedData:             subscribeFeedData,
    SubscribeFeedTokens:         []string{"NSE:26000"},
    WebSocketConection:          webSocketConnection1,
  }
err = Firstock.InitializeWebSockets({{userId}}, model)
fmt.Println("Error:", err)
if conn1 != nil {
  err = Firstock.Subscribe(conn1, []string{"BSE:1"})
}
fmt.Println("Error:", err)
time.Sleep(25 * time.Second)
err = Firstock.Unsubscribe(conn1, []string{"NSE:26000", "BSE:1"})
fmt.Println("Error:", err)
time.Sleep(25 * time.Second)
err = Firstock.CloseWebSocket(conn1)
fmt.Println(err)

Response Structure

1. Acknowledgement Response

Body

Number of Acknowledgements for a single subscription will be the same as the number of scrips mentioned in the key (k) field.

Response:

{
    "best_buy": [
        {
            "price": 728,
            "quantity": 556697,
            "orders": 31
        },
        {
            "price": 727,
            "quantity": 1500222,
            "orders": 124
        },
        {
            "price": 726,
            "quantity": 1446656,
            "orders": 100
        },
        {
            "price": 725,
            "quantity": 1547075,
            "orders": 172
        },
        {
            "price": 724,
            "quantity": 711615,
            "orders": 49
        }
    ],
    "best_sell": [
        {
            "price": 729,
            "quantity": 241310,
            "orders": 31
        },
        {
            "price": 730,
            "quantity": 651336,
            "orders": 50
        },
        {
            "price": 731,
            "quantity": 2035051,
            "orders": 42
        },
        {
            "price": 732,
            "quantity": 418208,
            "orders": 36
        },
        {
            "price": 733,
            "quantity": 869381,
            "orders": 171
        }
    ],
    "c_exch_feed_time": "11-Jul-2025 09:17:58",
    "c_exch_seg": "NSE",
    "c_net_change_indicator": 45,
    "c_symbol": "14366",
    "i_average_trade_price": 730,
    "i_buy_depth_size": 5,
    "i_closing_price": 733,
    "close_price": 733,
    "i_feed_time": 1752205678,
    "i_high_price": 733,
    "i_last_trade_quantity": 135,
    "i_last_trade_time": 1752205676,
    "i_last_traded_price": 729,
    "i_low_price": 727,
    "i_lower_circuit_limit": 659,
    "i_net_price_change_from_closing_price": 2,
    "i_open_price": 733,
    "i_seconds_since_boe": 1752205678660009700,
    "i_sell_depth_size": 5,
    "i_total_buy_quantity": 13658079,
    "i_total_open_interest": 2616021929,
    "i_total_sell_quantity": 26150279,
    "i_total_tradevalue": 6467553260,
    "i_upper_circuit_limit": 806,
    "i_usecs": 660009635,
    "i_volume_traded_today": 9770825,
    "i_yearly_high_price": 1767,
    "i_yearly_low_price": 629
}

2. Updates Response

Body

Response:

{
  "best_buy": [
        {},
        {},
        {},
        {},
        {}
    ],
    "best_sell": [
        {
            "price": 729,
            "quantity": 241310,
        },
        {},
        {
            "quantity": 2035051,
            "orders": 42
        },
        {},
        {
            "price": 733,
            "quantity": 869381,
            "orders": 171
        }
    ],
    "c_exch_feed_time": "11-Jul-2025 09:17:58",
    "c_exch_seg": "NSE",
    "c_net_change_indicator": 45,
    "c_symbol": "14366",
    "i_average_trade_price": 730,
    "i_buy_depth_size": 5,
    "i_closing_price": 733,
    "close_price": 733,
    "i_feed_time": 1752205678,
    "i_last_trade_quantity": 135,
    "i_last_trade_time": 1752205676,
    "i_low_price": 727,
    "i_lower_circuit_limit": 659,
    "i_net_price_change_from_closing_price": 2,
    "i_open_price": 733,
    "i_seconds_since_boe": 1752205678660009700,
    "i_sell_depth_size": 5,
    "i_total_buy_quantity": 13658079,
    "i_total_open_interest": 2616021929,
    "i_usecs": 660009635,
    "i_volume_traded_today": 9770825,
    "i_yearly_high_price": 1767,
    "i_yearly_low_price": 629
}

Note: Only delta values are included in the output. Default values such asnull and large placeholder integers (e.g.,9223372036854776000) are automatically ignored, and their corresponding keys are omitted to ensure a concise and accurate data payload.

Unsubscribe Feed

Body

Below is the general JSON body for the Unsubscribe Feed API request. All fields marked as Mandatory must be included.

Request

Multiple Token

{"action":"unsubscribe","tokens":"BSE:500470|NSE:26000"}

action = Type of request; unsubscribe indicates you want to stop receiving live market data for the specified tokens.

tokens = Parameters for unsubscription. In Multi Token, we can multiple tokens in single request.

Single Token

{"action":"unsubscribe","tokens":"NSE:2885"}

action = Type of request; unsubscribe indicates you want to stop receiving live market data for the specified tokens.

tokens = Parameters for unsubscription. In Single Token, we can send only one tokens in single request.

"No Response will be sent for Unsubscribe Action from Websockets for Acknowledgment"