Learn
Zero Days To Expiration SPX Options Trading
0DTESPX.com is a simulated trading platform for zero-days-to-expiration SPX options. Replay any past session or trade today's market in real time, track positions and greeks, and build and backtest strategies. These guides cover every feature, plus the public API.
Getting started
Core concepts
A primer on zero-days-to-expiration SPX index options.
Persistent accounts with a continuous balance, traded one day at a time.
Reading bids, asks, mid prices, and live delta across every strike.
Market, limit, stop, and multi-leg orders and how they fill.
Tracking direction, cost basis, and realized vs unrealized P&L.
FINRA maintenance-margin rules for shorts, spreads, and condors.
The brokerage fee schedule applied to every order.
What happens to open options at the 4:00 PM ET close.
Trading & research
Take an idea from backtest to live: the Research → Trade funnel.
Paper trade today's session against the real-time tick stream.
Rehearse trades by hand on any past day, with a clock you control.
Define a 0DTE strategy with a structured form.
Describe a strategy in plain English and let the AI author it.
Every saved strategy owns backtest results over the full history.
Combine saved strategies into one aggregated results view with equal $100k sleeves.
Run a saved strategy hands-free against the live session — coming soon.
Live and historical SPX/VIX data, option chains, and overlays.
API reference
Base URL, auth, access levels, and conventions.
An end-to-end paper-trading tutorial with copy-pasteable curl examples.
The market-data credit budget and per-endpoint costs.
Create accounts, open sessions, advance the clock, and read financials.
Place, preview, and cancel orders, including multi-leg.
Read computed positions with delta and P&L, and the transaction log.
Sessions, strikes, history, and option-chain snapshots.
Trade today's session: orders, positions, idempotency.
Preview, save, and read strategies and their backtest results.
Combine saved strategies into portfolios with read-time aggregated results.
Run a saved strategy as a live bot: sessions, lifecycle, and per-session data.
Real-time market data and per-session event channels.