Who builds ScalperSense, and how

ScalperSense is an independent Indian market-data site, built and run by Chanakya Devraj. It reads what NSE, BSE, AMFI and a handful of other public sources publish, does the arithmetic that turns those numbers into a reading, and writes the answer down in English. This page is the accounting: what the site is, where every figure comes from, what is computed here rather than copied, and who is responsible when something is wrong.

What this site is

Nineteen pages, all free, no account. The core of it is the NSE option chain — open interest, implied volatility, PCR and max pain for NIFTY, BANKNIFTY, FINNIFTY and MIDCPNIFTY, refreshed through the session — with the BSE chain for SENSEX and BANKEX alongside it. Around that sit the pages that answer the questions the chain raises: what the day actually did (Highlights), how open interest got to where it is (OI & IV Flow), who was buying (FII/DII), which stocks look strong (Screener, Stock Picks), and what is coming that might gap the market open (Events, IPO Hub).

The Why page walks through each of those in detail with worked examples. This page is about the machinery behind them.

Why it exists

The NSE option chain publishes several hundred rows per index — strike after strike of open interest, change in open interest, implied volatility, volume and bid/ask. All of it is free, and all of it is already public. Nothing about getting the data is hard.

What is tedious is the step after: working out which strikes are carrying enough open interest to act as walls, whether today's implied volatility is expensive against its own recent range, what the at-the-money straddle is pricing as the expected move, and whether the day's change in open interest reads as writing or as covering. Those are a fixed set of calculations over numbers anyone can download. Doing them by hand, four indices at a time, every few minutes, is not analysis — it is data entry. ScalperSense exists to do that part on a server and hand back the sentence at the end of it.

Where every number comes from

Nothing here is licensed or proprietary. Every input is a public endpoint, and each page's figures trace back to one of these:

• Option chains — NSE's own option-chain and contract information endpoints, for the four index underlyings, plus BSE's equivalent for SENSEX and BANKEX. Strike-level OI, change in OI, IV, volume and quotes come from there unaltered.
• Equity quotes and market breadth — NSE's quote and live-analysis endpoints for prices, advance/decline, gainers and losers, and delivery percentage; NSE's own security list for the tradable universe.
• Price history — NSE's end-of-day history feed for stocks, and NSE Indices for index open/high/low/close. Both are daily bars, read after the close.
• Institutional activity — NSE's daily provisional FII/DII cash figures and its participant-wise open interest report. Both are end-of-day and both are marked provisional by the exchange; they get revised, and we show what the exchange currently says.
• Mutual funds — AMFI's daily NAV file, which lists every scheme in India once per business day. Returns, drawdowns and rankings on the Funds page are computed from that NAV history, not taken from a fund house's own factsheet.
• ETFs — two sources joined, which is the point of the page. AMFI's NAV file says what a unit is worth; NSE's ETF endpoint says what it last traded at. The gap between them is a real cost that no return figure reports, and the ETF page is built on it. The price history behind those figures is accumulated here — one snapshot a day, stored and added to — rather than re-read from the exchange's archive each night.
• REIT and InvIT distributions — NSE's corporate-actions filings, which state each payout and, in prose, how it splits between interest, dividend and repayment of capital. That split is the only public source for how a distribution is taxed, and the ETF & trusts page parses it rather than quoting the headline yield alone.
• Corporate calendar and IPOs — NSE's corporate actions and results calendar, and the exchange's IPO subscription figures.
• Pre-market global cues — index, commodity and currency quotes for the overnight session, used only on the Outlook page to describe what happened while India was shut.
• News headlines — public RSS feeds from Indian mainstream outlets. Headlines link back to the publisher; we do not claim authorship of any of them.

Where a source is delayed or provisional, the page says so on the page rather than here. Market data on this site is not real-time-tick data: it is the exchange's published figures, polled on a schedule, and it can be a minute or two behind.

What is computed here

The distinction that matters is between the numbers we relay and the numbers we produce. These are produced here, from formulas written on the site and applied identically every time:

• Max pain — the strike at which the total value of options expiring worthless is highest, computed by walking every strike and summing the cash settlement across the whole chain.
• Expected move — the at-the-money straddle price read as the market's own estimate of the range into expiry, with both breakevens printed alongside it.
• OI buildup bias — each near-the-money strike's change in open interest classified as long buildup, short buildup, short covering or long unwinding, then weighted into a single bullish or bearish reading. It describes positioning that has already happened. It is not a forecast.
• IV rank — where today's implied volatility sits inside its own recent range, so "12% IV" becomes "dear" or "cheap" rather than a number with no reference point.
• Screener verdict — moving averages, RSI, delivery percentage and the 52-week range combined into one line of plain English per stock.
• Stock Picks — a once-daily ranking built after the close from roughly 400 sessions of price history per symbol, scoring trend, momentum and volume.
• ETF rankings — the median premium or discount to NAV over a year, median daily turnover, and tracking difference against the fund's own peer group, computed from our own accumulated price history joined to AMFI's NAV history. Returns are shown but deliberately excluded from the score.
• Trust yields — trailing twelve-month distributions over the current price, split by tax treatment, with an after-tax range rather than a single figure because the dividend leg depends on a regime choice the underlying companies make. An illustration of the published rules, not advice.
• Fund rankings — rolling three-year returns, downside capture and maximum drawdown, computed per scheme from AMFI NAV history and ranked inside the scheme's own SEBI category so equity funds are not compared against debt.

Every one of these is arithmetic, not a model. None of them is backtested, none is fitted, and none of them knows anything about tomorrow. The cheat sheet spells out how to read the buildup classifications, and the glossary defines each term with a worked Indian-market example.

Keeping our own score

A site that prints directional readings should be checkable. The Scorecard exists for that: every directional call the site makes is written down when it is made, with the level and the reasoning, and scored later against what the market actually did. Misses stay on the page next to the hits. A record you can only see when it flatters the author is not a record.

How the site is built and run

It is a Node.js application on a single small server in Mumbai, run by one person. A background scheduler polls the exchange endpoints on the market's clock — and stands down on the roughly twenty days a year the exchange is shut — so pages are warm before anyone opens them rather than triggering a fetch on arrival. Anything you save (watchlist, journal, alerts) is kept in your own browser and never uploaded.

There is no account system, no paywall, no login and no email list. Nothing on the site is gated.

What this site deliberately isn't

Being clear about this is the point of the page:

• Not investment advice. We are not registered with SEBI as an Investment Adviser or as a Research Analyst, and nothing here is a recommendation to buy or sell anything. The disclaimer sets this out in full.
• No tips and no signal service. There is no paid group, no channel, no subscription tier and no "calls" for sale. Anyone soliciting money in this site's name is not us.
• No broking, no order routing, no custody. The site cannot place a trade and never asks for a broker credential.
• No data resale. The exchange data here is presented for reading. It is not offered as a feed or an API for anyone else's product.

How it pays for itself

Advertising, and nothing else. The site carries display ads; which ads appear is decided by the ad network, not by us, and an ad running here is not an endorsement. There is no affiliate revenue, no paid placement, and no arrangement under which a broker, fund house or company can influence what a page says about them. No ranking, verdict or score on this site is for sale, and none of them are adjusted by hand.

What we collect while you read is set out in the privacy policy.

Corrections

Market data goes wrong in specific ways: an upstream endpoint changes shape, a holiday is missed, a corporate action is not adjusted for, a figure is revised by the exchange after we read it. When a number here is wrong we would rather hear about it than not.

If something looks off, tell us through the contact form — the page, the figure and roughly when you saw it is enough to find it. Reports about incorrect data get looked at first, and the fix ships as soon as the cause is understood.

Who runs it

My name is Chanakya Devraj, and I build and run ScalperSense on my own. There is no team behind it, no newsroom, no outside funding and no institutional backer — every page, every formula and every line of the writing here is one person's work.

The rest of this site says "we". This section says "I", because this is the part where the difference matters.

I'm a technologist by trade and by temperament: my instinct with any system is to take it apart and find out how it actually works, and the Indian option chain is a system I wanted to understand. So I built the thing I wanted to read.

On markets themselves I am a learner — and I expect to still be one in ten years, because the honest position on trading is that nobody graduates. I am not a SEBI-registered investment adviser, not a research analyst, not a fund manager and not a professional trader, and I would rather say so at the top of this section than bury it at the bottom of a page.

That isn't a disclaimer bolted on at the end. It is the reason the site is built the way it is:

• Because I had to learn what max pain and IV rank meant before I could use them, there is a glossary of 109 terms and ten written topic pages — the explanation I wanted when I started, and couldn't find in one place.
• Because a number with no context taught me nothing, every data page carries a written guide on what its figures mean and — the part almost nobody publishes — where they mislead.
• Because I didn't want to grade my own homework, the Scorecard records every directional call this site makes and scores it against what actually happened. The misses stay on the page.
• Because I am clear about what I don't know, nothing here is advice, no verdict is for sale, and no ranking is ever adjusted by hand.

A site built by an expert would probably assert more. This one shows its arithmetic instead — which is what I would want from a site I hadn't built myself.

If something here is wrong, I would genuinely rather know than not. The contact form reaches me.

Contact

Questions, corrections, or a suggestion for what to build next: the contact form reaches the person who maintains the site. We read everything. We can't advise on trades, recommend positions or tell anyone what to buy — see the disclaimer for why that isn't something we're able to do.