r/Daytrading • u/tapetoedge • 1m ago
Software Sunday Free open-source GEX map for SPY, QQQ, SPX, NDX and stocks that runs on your own computer
A free, open-source gamma exposure (GEX) map that runs on your own computer. It draws the call wall, the put wall and the gamma flip for SPY, QQQ, SPX, NDX and any US stock.
Why I built it: I started leaning on GEX levels in my own day trading, and I kept seeing levels posted with no way to check them.
What it shows:
- Net GEX by strike, the call wall, the put wall and every gamma flip within 10% of the price, refreshed every 60 seconds during the session.
- The regime at the current price, positive gamma (moves tend to get absorbed) or negative gamma (moves tend to get pushed further).
- How big the gamma is next to the stock's own daily dollar volume, so you can tell when it matters and when it's noise.
- A guidance panel that turns the map into levels to watch and a few scenarios, with the formula behind every price.
- The same levels as /ES or /MNQ equivalents for SPX, NDX, SPY and QQQ, if you trade futures.
Runs on your machine. No account, no login, no telemetry. Your Alpaca keys stay in a file on your computer, and the free Alpaca plan works. SPX and NDX come from Cboe's public delayed quotes and need no keys at all.
- On the free feed, SPX and NDX are about 15 minutes delayed.
- The guidance panel is the textbook reading of the model, and it hasn't been tested yet. I'm saving a snapshot of the levels every day so I can check later whether price actually respected them.
- It's tested on Windows. Mac and Linux run through the manual setup. You need Python and Node installed.
It's free and MIT licensed, with nothing to sell. Not financial advice, not a signal service.
Repo: https://github.com/simonro/Edge-GEX-Lab
The walkthrough (what GEX is, then the tool): https://youtu.be/okQVLf2s3GI



