Learn
Zero days to expiration SPX options trading
0DTESPX.com is a simulator for zero-days-to-expiration SPX options — every balance is simulated, so mistakes are free. Practice any past trading session, backtest a strategy across all of them, then trade today's market in real time. These guides cover every feature, plus the public API that drives it.
The path
Learn it, rehearse it, prove it, then go live.
Four steps, in the same order as the sidebar — each one hands off to the next.
Learn the ground rules
0DTE SPX options expire the same afternoon you trade them: cash-settled, European-style, and quick to punish sloppy risk management. Three short reads cover the essentials — 0DTE & SPX options for the instrument, buying power & margin for what a position costs you, and end-of-day settlement for what happens at the 4:00 PM ET close.
Practice on any past day
Practice is a $100,000 sandbox for any past trading session, and the clock belongs to you: drop in mid-morning, scrub forward and back, and place trades on the full option chain exactly as it stood. Trade the day, watch it settle — then rewind and try a different idea. The quick start walks your first session click by click.
Turn an idea into a strategy
When a trade starts feeling repeatable, encode it. The strategy builder turns structure, entry, and exit into precise rules — or describe it in plain English and let the assistant write it. Every saved strategy is backtested across the full history, and portfolios combine the keepers. The research guide walks the whole funnel.
Trade the market's clock
A live account paper-trades today's session against the real-time tick stream, with a continuous balance that carries forward like a real brokerage — same chain, same engine, same settlement as everywhere else. Afterwards, replay any settled day to review your execution. And when a strategy has earned it, a bot trades it hands-free.
REST + WebSocket API
Drive the whole platform from a terminal.
Everything the app does, the API does — accounts, orders, strategies, backtests, and market data over REST, plus the live stream over WebSocket. The end-to-end walkthrough is a full paper-trading session in copy-pasteable curl.
# every trading session, no auth required curl -s "https://api.0dtespx.com/market-data/sessions" # the full HTTP + WebSocket reference curl -s "https://www.0dtespx.com/openapi.yaml" # building with an AI agent? one machine-readable index curl -s "https://www.0dtespx.com/llms.txt"
All guides
The complete index.
One page per feature — the same list as the sidebar.