Gamma exposure (GEX) estimates the hedging obligation embedded in today's options. Market makers take the other side of customer order flow and hedge to stay delta-neutral; gamma measures how quickly that hedge has to change as the index moves. Summed across every strike expiring today, it produces a map of where mechanical buying and selling pressure sits on the price axis — and whether that pressure will lean against the tape or chase it.

Delta is how much an option's value changes when the index moves. Gamma is how fast that delta itself changes — it concentrates at the money and intensifies sharply as expiration approaches. This tool reads the live chain, backs out each strike's implied volatility from its quotes (index feeds don't publish per-contract greeks, so they're modeled with Black-Scholes), and converts gamma into dollars at each strike:

Each bar on the chart is the net of the two sides at one strike, in dollars of hedging per 1% index move. Some tools quote per 1-point move instead — those read about index÷100 smaller (roughly 74× on SPX). Same quantity, different yardstick.

The sign of dealers' net gamma decides whether their hedging stabilizes the tape or destabilizes it:

Gamma concentrates at the money and intensifies as expiration approaches — the same strike carries far more gamma with hours left than with weeks left. Same-day contracts are now the majority of index options volume, so most of the hedging that actually moves the index or ETF in view (SPX, NDX, RUT, SPY, QQQ) intraday lives in options that die at today's close. This tool scopes to today's expiration only to isolate the gamma that matters for this session, rather than diluting it with next month's. The 0DTE / Week / All toggle widens that scope when you want it — Week folds in every expiration within seven days, All takes everything listed — but 0DTE is the default and the sharpest read for same-day hedging.

Start with the regime: the banner and the sign of Net GEX set the frame — is hedging leaning against the tape today, or chasing it? Then place spot relative to the flip; the gap between them is the cushion before the regime changes. Treat the walls as zones rather than lines — the strongest positive and negative gamma concentrations, where hedging pressure is densest (if a wall sits outside the visible window, its stat card says so). The expected-move band is on by default to frame whether a move is ordinary or stretched; toggle any line off in the legend to declutter. The tool refreshes silently every 60 seconds during market hours, and 0DTE levels migrate — the wall that mattered at 10am may not be the one that matters at 2pm.

Below the chart, two time-series panels record the day as it unfolds. Net GEX trace plots the whole book's net gamma minute by minute — watch it climb deeper into long-gamma (pinning) or fall through zero into short-gamma (trending). Spot vs key levels plots spot against the gamma flip and shades the gap between them: green when spot sits above the flip (a long-gamma cushion), red once it breaks below. The Walls toggle on that panel overlays the current call and put walls as reference lines, so you can watch spot navigate between them — at the cost of zooming the view out, which is why it's off by default. Both panels build the whole session and are shared across everyone viewing the tool, so they show the full day even if you opened the page at 2pm. A theme toggle (the ◐ button) switches between the dark terminal and a lighter studio skin; your choice is remembered.

Before 9:30 ET the live feed doesn't yet carry today's expiration, so the view is built from the prior session's chain via the daily-expiration roots (SPXW, NDXP, RUTW for the indices; SPY and QQQ carry their own 0DTE directly). It weights the bars by the most recent session's closing open interest — real positioning, the same prior-close OI other 0DTE tools show before the open — and labels the as-of date in the banner. Closing OI posts on the data provider's lag that clears through the morning (typically by about 7:30 ET); until it posts for the latest session, the tool automatically steps back to the most recent session that does carry OI, and only as a genuine last resort falls to traded volume, labeled as such. The spot line holds at the prior close until the bell. At the open everything switches to the live chain automatically — real-time open interest, live quotes, live gamma. Intraday, the Open interest / Volume toggle offers two lenses on the same chain: OI is positioning that existed as of this morning; volume is the flow happening today.

Modeled, not observed. Public chain data shows quotes, volume, and open interest — not who is long or short each contract. Like every GEX tool, this one assumes dealers are net long calls and net short puts against customer flow; where that assumption is wrong at a strike, the sign there is wrong too.

Open interest is a daily snapshot. It reflects positioning as of the prior close, not what's been built this morning — the intraday Volume lens is there for that. Pre-market, the closing figure posts on a provider lag; the tool uses the most recent session that actually carries it and shows the as-of date, rather than guessing.

Levels are zones. High gamma is associated with pinning, not guaranteed pinning. News, macro prints, and thin liquidity run straight through walls.

Context, not signals. Nothing here is a buy or sell trigger. GEX is a map of where hedging pressure may concentrate — most useful alongside price action, trend, and volatility, never instead of them.

Every stat card up top has its own short explainer too — tap the i on any card.