Why TradingView cannot compute GEX by itself
A dealer gamma level is computed from the option chain: the open interest at every strike, for every expiration, with the implied volatility and the greeks that go with it. A TradingView chart holds price and volume, plus whatever a Pine script can derive from them. Pine has no access to an option chain, so no script can compute gamma exposure from the chart alone.
That single fact explains why two indicators with the same name can draw lines 40 points apart. The maths is public and not especially hard; the data is the expensive part. Anything that shows a Zero Gamma on TradingView has to bring that number in from outside — the only question is how.
The three kinds of GEX indicator you will find
You type the levels in. The script draws lines where you tell it to. Honest, usually free, and it is a drawing tool: you still need somewhere to get today's numbers, and you repeat the work every morning.
The script approximates from price and volume. No strikes, no open interest. It may be a perfectly good indicator on its own terms, but what it draws is not dealer gamma, and it will disagree with the chain on exactly the days the chain matters.
The numbers are computed off the full chain and shipped inside the script. A service reads the chain, computes the levels and publishes them within the indicator, so the line on the chart is the number the service computed. That is how GexVision works.
A quick test for any of them: ask where the open interest comes from, and how often the levels refresh. If the first question has no answer, the level is not coming from the chain.
How the GexVision indicator works
GexVision reads the full chain of 95 symbols — SPX, NDX, SPY, QQQ, IWM, DIA and large US stocks — computes Zero Gamma, the Call Wall, the Put Wall and Max Gamma, and refreshes them every five minutes during the session. The data is delayed about 15 minutes.
Those levels travel to TradingView inside an invite-only indicator: the script carries the computed numbers, so nothing is typed by hand and the same levels appear in the web terminal and in the Bookmap add-on.
Index levels are also converted to the matching futures price, so the line lands where the futures chart actually trades instead of where the cash index does.
Setting it up
1. Start the free trial and open your dashboard. 2. In the TradingView → indicator access card, save your TradingView username — the one in the address of your profile, tradingview.com/u/your-user, not your email and not your display name. 3. Access is granted from our side; the docs promise within 24 hours and it is usually the same day. You get an email when it is on.
4. In TradingView, open the chart you trade, click Indicators and look under Invite-only scripts. Add it once: from then on the levels refresh on their own, with no code to copy and no Pine editor to open.
The step-by-step version, with screenshots, is in the setup guide.
How to check the levels are right
Compare them against the public levels page for the same session. gexvision.io/levels/SPX publishes the levels the session opened with and what price did against them, for SPX, NDX, SPY, QQQ and nine more symbols, with no account needed. If the line on your chart and the number on that page disagree for the same session, something is stale — tell us.
The other check is movement: the levels should change as the chain changes, not sit frozen for days. Open interest updates once a day, but price and 0DTE options move gamma within the session, which is why the levels refresh every five minutes and the session-opening values stay visible next to them.