FAQ

Answers to the questions we hear most often. If yours isn't here, get in touch.

Is this real trading?

No. 0DTESPX.com is a paper-trading simulator for education and research. No real orders are ever placed, and no real money is at risk. Nothing on the platform is investment advice.

Do I need an account?

You can watch live and recent market data as a visitor. To place trades, build strategies, or run backtests, you need a free account. See Access & accounts.

What does it cost?

Nothing. Registering an account unlocks everything — the simulator, the strategy builder, backtesting over the full recorded history, 1-second data, all historical dates, and a custom fee schedule. There is nothing to pay for.

What's the difference between historical and live mode?

In historical mode you replay a past session and control the clock — jump forward, rewind, and replay as much as you like. In live mode you trade today's session against the real-time market, with no time travel. See Historical replay and Live trading.

Why was my order rejected for buying power?

Naked short options reserve a lot of margin — strike × 20% × quantity × 100, which for a 5950 strike is around $119,000 per contract. Either start the simulation with more capital, or trade a defined-risk spread, which needs far less. See Buying power & margin.

My SPX limit price was rejected — why?

SPX option orders must land on the right price tick: single-leg orders priced at or below $3.00 use a $0.05 tick, above $3.00 a $0.10 tick, and multi-leg orders always $0.05. So $3.05 is invalid (the next valid price above $3.00 is $3.10). See Orders & order types.

How are fills priced?

Market and triggered stop orders fill at the mid-price. Marketable limit orders fill at your price or better. Pending limit orders fill once the market reaches your level. Full rules are in Orders & order types.

What happens to my options at the end of the day?

At 4:00 PM ET the session settles: out-of-the-money options expire worthless, and in-the-money options are exercised (if long) or assigned (if short), cash-settled at (underlying − strike) × 100. See End-of-day settlement.

How do strategies and backtests relate?

You author a strategy with the form builder (an AI assistant is being rebuilt), and its backtest results measure it across the full recorded history. Strategies are immutable once saved — identical configurations share one strategy and one set of results — so the results you read always describe exactly the logic you saved. To change the logic, clone the strategy and edit the copy.

Can I use the API?

Yes — every feature is available over an HTTP + WebSocket API. Start with the API overview, or read the canonical spec at /openapi.yaml.

How far back does the data go?

Registered accounts can access every historical session — hundreds of past trading days. Visitors can see the most recent completed session. See Market data & charts.

Is my data private?

See our Privacy Policy for how we handle your data, and the Terms for the rules of using the service.