FAQ

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.

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.

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.

Practice is account-less: each trading day is a one-click $100,000 sandbox — nothing to create, and every day stands alone. 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, Live trading, and Replay. Broker accounts are coming soon.

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.

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.

Market orders fill at the natural price — the ask when buying, the bid when selling — right away. A limit order is different in two ways. If the market had to come to it, it fills at your own limit price, never at a better price the market flickered to for an instant — while one you price past the market crossed the spread on purpose and fills at the market it crossed, as of the moment that price was set. Usually that is when you placed the order, but giving it a new price starts it over, so a re-priced order can fill better than the price shown on it. Pricing at the mid is not crossing: that order rests. Waiting differs the same way. An order the market has to come to fills only once the market has held at or through its price for three consecutive seconds, while one priced past the market does not wait at all — it fills the instant its price reaches through the market, which for an order priced that way from the start is the second you place it. A one-second blip to your price fills nothing; one that goes through it does. What the market has to reach is 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 slippage setting makes it go a little further still. A triggered stop is the marketable exception — it takes three seconds to fire, then fills at that mid-based price. Full rules are in Orders & order types.

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 order harder to fill, the way real fills are: the market has to move that much further past your price before the order goes through, and any order that fills at the market prints that much worse — though never worse than the natural price itself. It applies identically in practice, live trading, and every backtest you view — backtest results are computed at zero slippage, so your setting is charged against them as a flat per-contract cost when you view them. You can change it or set it to zero at any time. See Orders.

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 for calls and (strike − underlying) × 100 for puts. See End-of-day settlement.

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.

Yes — trading bots run a saved strategy hands-free against the live session, each with its own risk policy and a continuous balance that carries day to day. Create one in the app, or drive it from the Bots API.

Live trading 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, so orders aren’t accepted. 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.

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

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

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