FAQ

Q: 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.

Q: What's the difference between practice and live trading?

Practice is account-less: each trading day is a one-click $100,000 sandbox — nothing to create, no starting capital to choose. You trade a trading session and control the clock — jump forward, rewind, and replay as much as you like. A live account trades today's session against the real-time market, with no time travel — but once a live day settles you can replay it read-only, scrubbing the clock back through the day to review how it played out (you just can't change it). A live account keeps a continuous cash balance that carries day to day. See Accounts & trading days, Practice, and Live trading. Broker accounts are coming soon.

Q: How are fills priced?

Market orders fill at the natural price — the ask when buying, the bid when selling. Limit and stop orders execute at a mid-based price: the mid of the bid/ask, rounded one tick in the market maker's favor when the spread is an odd number of ticks (and the natural price when the spread is exactly one tick). Your account's slippage setting then worsens limit/stop fills slightly, modeling real execution drag. Full rules are in Orders & order types.

Q: What is slippage, and can I change it?

Slippage is a per-account setting in Settings → Simulator Costs — a multiple of $0.05 (default $0.05, up to $1.00) that makes every limit and stop fill slightly worse than the ideal mid, the way real fills are. It applies identically in practice, live trading, and every backtest you view, and you can change it or set it to zero at any time. See Orders.

Q: How do strategies and backtests relate?

You author a strategy with the form builder or the AI assistant, and its backtest results measure it across the full history. Strategies are immutable once saved, so the results you read always describe exactly the logic you saved. To change the logic, clone the strategy and edit the copy.

Answers to the questions we hear most often.

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 history, 1-second data, all historical dates, and a custom fee schedule. There is nothing to pay for.

What's the difference between practice and live trading?

Practice is account-less: each trading day is a one-click $100,000 sandbox — nothing to create, no starting capital to choose. You trade a trading session and control the clock — jump forward, rewind, and replay as much as you like. A live account trades today's session against the real-time market, with no time travel — but once a live day settles you can replay it read-only, scrubbing the clock back through the day to review how it played out (you just can't change it). A live account keeps a continuous cash balance that carries day to day. See Accounts & trading days, Practice, and Live trading. Broker accounts are coming soon.

Why was my order rejected as a naked short?

The platform is defined-risk only: an order that would leave an uncovered short option is rejected with naked short positions are not allowed, no matter how much capital the account has. A short put must be covered by a long put and a short call by a long call — a long call does not cover a short put. Add the matching long leg (a cheap, far out-of-the-money one will do) to turn it into a spread. This is the same rule the strategy builder enforces. 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 under $3.00 use a $0.05 tick, at $3.00 and above 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 orders fill at the natural price — the ask when buying, the bid when selling. Limit and stop orders execute at a mid-based price: the mid of the bid/ask, rounded one tick in the market maker's favor when the spread is an odd number of ticks (and the natural price when the spread is exactly one tick). Your account's slippage setting then worsens limit/stop fills slightly, modeling real execution drag. Full rules are in Orders & order types.

What is slippage, and can I change it?

Slippage is a per-account setting in Settings → Simulator Costs — a multiple of $0.05 (default $0.05, up to $1.00) that makes every limit and stop fill slightly worse than the ideal mid, the way real fills are. It applies identically in practice, live trading, and every backtest you view, and you can change it or set it to zero at any time. See Orders.

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 or the AI assistant, and its backtest results measure it across the full history. Strategies are immutable once saved, so the results you read always describe exactly the logic you saved. To change the logic, clone the strategy and edit the copy.

Yes. Flip it to public and send someone the link — public means "anyone with the link", not "listed": there's no directory, and the id can't be guessed. Anyone holding the link (even signed out) can view it, and any registered user can clone the configuration as their own. Private is the default. See the Strategies API for the mechanics.

Can strategies run automatically?

Not yet — trading bots, which run a saved strategy hands-free against the live session with a per-bot risk policy, are coming soon. The concept and API are documented today so you can see what's ahead.

Why can't I open a live session right now?

A live session needs the market open and live data flowing — outside regular trading hours (9:30 AM–4:00 PM ET, Monday to Friday) there's nothing live to trade. Practice works around the clock on any past session; it's the same engine and chain, just on your clock instead of the market's.

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.