What's available
- Index prices — SPX and VIX through the session.
- Expected move and related series — a sense of how big a move the market expects.
- Option-chain snapshots — every strike’s calls and puts at a point in time, with bids, asks, and live delta.
- Available strikes for any session.
Historical coverage spans hundreds of past trading days.
Resolution by access level
Market data is delivered at a sampling rate that depends on whether you're signed in — a visitor gets a 30-second feed, a registered (free) account gets 1-second. Same minute, same path; the difference is how densely it's sampled:
3 points across the minute — the shape is blocky.
60 points — every wiggle is resolved.
Today's in-progress session is the exception: it streams at 1-second resolution for everyone until it closes. Visitors can access the most recent completed session; registered accounts can access every historical date.
Live charts
The live chart shows the real-time SPX price with configurable overlays — expected move, VIX, total extrinsic value (the time premium summed across the whole chain), and out-of-the-money bids (the bid prices of all OTM options, summed). Play the session and watch the two chain-wide totals decay toward zero into the close — a useful at-a-glance gauge of how much premium is left in the day. No account is needed to watch the chart, though signing in unlocks finer resolution and more history.
How big a move the day is pricing in.
The volatility index through the session.
Time premium summed across the chain — gone by the close.
Summed bids of every out-of-the-money option.
The two chain-wide premium totals — extrinsic value and OTM bids — bleed toward zero into the close, a quick gauge of how much premium is left in the day.
Historical charts
For any past session, you can view the index price path and pull up the option chain at any moment in the day, with delta recomputed for that timestamp. This is the same data practice replays — which is what makes the sandbox faithful: the quotes you trade against in practice are the session's actual quotes, not a model.
Real-time streams
Live market data is also available as a push stream over WebSocket — a 1-second aggregate feed and the latest option-chain snapshot. This is what keeps the live trading screen current tick by tick.
Two channels carry the live feed: a 1-second aggregate of SPX, VIX, and the chain-wide premium totals, and the latest option-chain snapshot. Building an integration?
WebSocket APIFair-use rate limits
Registered accounts have full access to the historical data, so market-data requests draw against a usage budget that keeps access fair. Visitor traffic isn't rate-limited because it can only reach the most recent session.