Live Quotes & Delayed Data

You've now pulled data two ways: delayed, from yfinance, and live, from OpenAlgo. They look similar in code, but the difference between them is the difference between studying the market and trading it. This chapter puts them side by side, decodes every field in a quote, and builds a small live quote board - the kind of thing you'd glance at all day.

A live quote board

A "quote" is the current snapshot of a stock. With OpenAlgo you can pull several at once and lay them out as a board, using the f-string alignment from Chapter 7:

import os

from openalgo import api

client = api(
    api_key=os.getenv("OPENALGO_API_KEY", "your_api_key_here"),
    host=os.getenv("OPENALGO_HOST", "http://127.0.0.1:5000"),
)

symbols = ["RELIANCE", "TCS", "INFY", "SBIN"]

# A live quote board - one row per symbol, aligned with the f-string tricks from Chapter 7.
print(f"{'Symbol':<12}{'LTP':>12}{'Prev close':>14}")
print("-" * 38)
for s in symbols:
    data = client.quotes(symbol=s, exchange="NSE")["data"]
    print(f"{s:<12}{data['ltp']:>12,.2f}{data['prev_close']:>14,.2f}")

Symbol               LTP    Prev close
--------------------------------------
RELIANCE        1,313.60      1,313.60
TCS             2,109.00      2,109.00
INFY            1,056.60      1,056.60
SBIN            1,034.60      1,034.60

Four live LTPs - last traded prices - in a clean, aligned table. This is the heartbeat of any trading screen: a loop over your watchlist, one quote each, refreshed as often as you like. (Here prev_close equals ltp because the sandbox is quiet; on a live feed during market hours they differ, giving you the day's change.)

What's in a quote?

A quote is more than one number. Pull the full record and you get the whole picture of supply and demand:

import os

from openalgo import api

client = api(
    api_key=os.getenv("OPENALGO_API_KEY", "your_api_key_here"),
    host=os.getenv("OPENALGO_HOST", "http://127.0.0.1:5000"),
)

q = client.quotes(symbol="RELIANCE", exchange="NSE")["data"]

print("RELIANCE - a full quote:")
for field in ["ltp", "prev_close", "open", "high", "low", "bid", "ask", "volume"]:
    print(f"  {field:<11}: {q.get(field)}")

RELIANCE - a full quote:
  ltp        : 1313.6
  prev_close : 1313.6
  open       : 0.0
  high       : 0.0
  low        : 0.0
  bid        : 0.0
  ask        : 0.0
  volume     : 0

Here's what each field means:

• ltp - last traded price, the single most-watched number.
• prev_close - yesterday's closing price; ltp - prev_close is the day's change.
• open / high / low - today's first price and its range so far.
• bid / ask - the best price someone will buy at (bid) and sell at (ask); the gap between them is the spread.
• volume - shares traded today, a gauge of activity.

Live versus delayed

Free feeds like yfinance are delayed - typically by about 15 minutes - while a broker feed like OpenAlgo is live. Put them head to head:

import os

import yfinance as yf
from openalgo import api

client = api(
    api_key=os.getenv("OPENALGO_API_KEY", "your_api_key_here"),
    host=os.getenv("OPENALGO_HOST", "http://127.0.0.1:5000"),
)

# Live: straight from the broker feed via OpenAlgo.
live = client.quotes(symbol="RELIANCE", exchange="NSE")["data"]["ltp"]

# Delayed: a free feed (yfinance) - good for study, but it lags the real market.
delayed = float(yf.Ticker("RELIANCE.NS").history(period="2d")["Close"].dropna().iloc[-1])

print(f"OpenAlgo (live)    : {live:>10.2f}")
print(f"yfinance (delayed) : {delayed:>10.2f}")
print(f"Difference         : {live - delayed:>+10.2f}")

OpenAlgo (live)    :    1313.60
yfinance (delayed) :    1313.60
Difference         :      +0.00

Right now the difference is zero - and that's instructive, not a bug. When the market is quiet or closed, the delayed feed has caught up to the same settled price, so the two agree. The gap only opens when price is moving:

In a fast-moving market those 15 minutes can be several percent - which is exactly why you study history on free delayed data, but place real orders on a live feed.

When do you actually need live?

The honest answer for a learner: not yet. Studying history, testing ideas, building the skills in this course - all of it is fine on free, delayed data. You only need a live feed when you're placing real orders and the exact current price matters. So learn on delayed data without guilt; reach for live (OpenAlgo) when you graduate to real execution.

Try it yourself

• Add HDFCBANK and ICICIBANK to the quote board and re-run it.
• Compute the day's change in the board: print ltp - prev_close as an extra right-aligned column.
• Run the live-vs-delayed comparison a few times during active market hours and watch whether the difference grows.

Recap

• A quote is a snapshot: ltp is the headline; prev_close, open/high/low, bid/ask (the spread) and volume fill in the picture.
• Build a quote board by looping your watchlist and printing an aligned table.
• Delayed feeds (yfinance, ~15 min) are perfect for study; live feeds (OpenAlgo) matter when you actually trade - the gap widens as the market moves.
• You only truly need live data when placing real orders.

There's one more way market data reaches you - and it's the opposite of everything in the last two chapters. Instead of asking for a quote each time, you can have prices streamed to you the instant they change. That's a WebSocket, and the next chapter explains the idea in plain words.