> ## Documentation Index > Fetch the complete documentation index at: https://docs.backquant.com/llms.txt > Use this file to discover all available pages before exploring further. # What is GEX? > Gamma exposure, dealer positioning, walls and support levels — explained **Gamma exposure (GEX)** measures how much underlying delta dealers are forced to hedge for every \$1 the underlying price moves. It's the single most useful concept for understanding why crypto sometimes pins to a strike, sometimes accelerates through it, and where the next reversal is likely to happen. ## The intuition in one paragraph When you buy an option, somebody else (a dealer / market maker) is the counterparty. To stay delta-neutral, the dealer hedges in the underlying. **Gamma** is the rate of change of delta with respect to the underlying price — so as price moves, the dealer's delta hedge has to be adjusted. **Net dealer gamma** at a given strike tells you how much hedging *pressure* exists at that level. Positive net gamma = dealers buy on dips and sell on rallies (stabilizing). Negative net gamma = dealers sell on dips and buy on rallies (amplifying). ## What we compute for you For every active option contract across Deribit, Bybit, OKX, and Binance, we compute the dollar gamma exposure (the USD impact per 1% spot move), sign it using the standard dealer-positioning convention (puts negative, calls positive), and aggregate the result per strike, per expiry, and per venue. You get the aggregated values directly — no reconstruction needed on your side. The [`/v2/gex/strike-profile`](/api/v2/gex/strike-profile) endpoint is the strike-level aggregation; [`/v2/gex/levels`](/api/v2/gex/levels) distils that further into the trader-actionable levels below. ## Key levels you'll see in the API The [`/v2/gex/levels`](/api/v2/gex/levels) endpoint gives you the trader-actionable levels distilled from the full strike profile: | Field | What it means | How traders use it | | ----------------------------------------------------------- | ------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------- | | **HVL** (Hedging Volume Level) | The strike where cumulative net gamma crosses zero closest to spot | The "gamma flip" — above HVL dealers stabilize, below HVL they amplify. Treat as a regime line. | | **call\_resistance** | The strike with the largest *positive* gamma above spot | The wall dealers will defend by selling into rallies. Common reversal zone. | | **call\_wall\_2 / call\_wall\_3** | Second / third strongest call walls above spot | Where price *might* pin if it breaks call\_resistance. | | **put\_support** | The strike with the largest positive gamma below spot | Dealers buy on dips into this level. Common bounce zone. | | **put\_wall\_2 / put\_wall\_3** | Second / third strongest put supports below spot | Successive support levels if put\_support breaks. | | **odte\_hvl / odte\_call\_resistance / odte\_put\_support** | Same three levels but computed from 0DTE-only options | Intraday-magnet levels; matters most in the last few hours of the trading day. | ## How to read them in practice **Spot above HVL with strong call\_resistance overhead** — expect mean-reverting price action, dampened vol, dealers selling into rallies toward the call wall. Good environment for premium selling. **Spot below HVL with strong put\_support below** — expect amplified moves on the way down, but a snap-back if price reaches put\_support. Dealers will start buying. **Spot crossing HVL** — regime change. The stabilizing/destabilizing balance flips. Watch for vol expansion right at the cross. **0DTE levels different from all-expiry levels** — common in the last hour before close. The 0DTE levels usually win for the close itself; the all-expiry levels matter more for the next session. ## What our `/v2/gex/levels` endpoint returns Out of the box, you get all-expiry walls + 0DTE walls: ```json theme={null} { "all_expiry": { "hvl": 67000, "call_resistance": 70000, "call_wall_2": 72500, "call_wall_3": 75000, "put_support": 64000, "put_wall_2": 60000, "put_wall_3": 58000 }, "odte": { "hvl": 67500, "call_resistance": 68000, "put_support": 66500 } } ``` Add `?include=ranked,max_pain,expected_move,zones` to also get: * `ranked` — top 10 strikes by absolute GEX (where the action concentrates) * `max_pain` — see the [max pain page](/concepts/max-pain) * `expected_move` — 1σ / 2σ implied range from ATM straddle * `gamma_flip_zones` — multiple-zero-crossing detail when the chain has more than one regime line ## Filtering by venue Aggregating across all four venues smooths noise but can also hide venue-specific positioning (e.g. Deribit dealers vs retail-heavy Binance options). Use `?exchanges=deribit` (or any subset) to recompute levels from a specific venue's chain only. ## Filtering by strike window Far-OTM strikes can have huge GEX from a small cluster of contracts and distort the picture. Use `?moneyness_min=0.9&moneyness_max=1.1` to clamp the analysis to ATM ±10%, or `?spot_window_pct=5` for a symmetric ±5% window. Both work on [`/v2/gex/strike-profile`](/api/v2/gex/strike-profile) and [`/v2/gex/strike-expiry-heatmap`](/api/v2/gex/strike-expiry-heatmap). ## Related concepts The strike where option writers profit most — different metric from GEX walls but often near them. Vanna, charm, vega — what they measure and how to use them alongside GEX. Why monthly/quarterly expirations dominate the GEX picture for a few days each month. Get GEX levels for BTC + ETH + SOL + HYPE in a single call.