You can see the dealer's book.
Where do the strikes go?
Build an SPX 0DTE options strategy on the gamma ladder — a condor, a strangle, a straddle, or any four legs you like. Read it against the measured dealer book for nothing. Then, when you want to know whether it has ever paid, test it over 1,080 archived sessions on real quotes and real settlement.
Open it in the terminal Pricing
Free, on any session, with no account
- Build it by clicking strikes. The gamma ladder is already the strike axis, so a leg lands where you click it, marked with what you did — −C a short call, +P a long put. Or start from a preset and widen it.
- The payoff at settlement, drawn on the same axis as the measured book: profit above the zero line, loss below, your breakevens marked, and the expected-move band behind it.
- Against the book. Where your short strikes sit relative to the measured call wall, the put wall and the zero-gamma flip — the thing no payoff calculator can tell you, because it needs a dealer book to compare against.
- The number that decides a short-premium trade. The win rate your strategy has to hit just to break even, against the probability the market is actually pricing today. Both are arithmetic off your own legs and today's quotes.
Then test it: 10 credits
- One press prices it 63 ways — seven widths of your own geometry across nine entry times — over every session in the archive. A single check would answer the wrong question: if one geometry loses, you cannot tell whether the idea is bad or only the strikes.
- And it does not stop at a shrug. When those 63 come back flat the run carries on for the same credits: where the whole structure sits relative to spot, then past the edge of the grid if the gradient was still climbing when it ran out, then eight standard 0DTE shapes — both sides of the strangle, the straddle and the condor, and the two vertical spreads. Up to 154 configurations. The answer stops being “not this” and becomes “not this, and here is what this archive does pay for”.
- Honest fills. Short legs sold at the bid, long legs bought at the ask, $1.25 a leg. That is not a conservative choice: measured on 13.1M prints of our own SPX 0DTE tape, the median print pays the full quoted half-spread and 92.6% execute exactly at the touch — so these fills are the median outcome, and optimistic above a handful of contracts.
- Every run ends somewhere. Move — change this by that much, one press. Hold — nothing left to gain, you are on the flat top, and here is what it pays. Or: the strikes are not the lever, and here are the structures that survived instead. A direction is recommended only when the marginal is ordered along the stretch you would actually walk, the gain clears the error bar on the difference, and a withheld holdout agrees. Three tests, all of which have to pass before it will tell you to do anything.
- It never names a best cell. With 63 variants the best one is best by chance, so the finding is the gradient and never the maximum. Everything it does recommend carries the count of what was tried, so a winner out of fifty-odd is read as a winner out of fifty-odd.
- It refuses trades that cannot pay their costs. A structure collecting less than its own commission is dropped rather than counted as a small win — measured, that is 6.8% of sessions at twice your width, and counting them is how a sweep talks itself into recommending strikes nobody would trade.
- What it pays, with the width of the answer. Per session and per month, on the holdout and on the full sample, each with the error bar that comes from session-to-session dispersion. When that bar crosses zero the page says so instead of quoting the mean.
What it will not do
- It never says which way. The tester answers distance — how far price usually travels, and what a structure earned. Per-print trade signing on SPX 0DTE is close to a coin flip, so a directional call built on it would be a guess wearing a number.
- It does not promise an edge. Most short-premium strategies win most days and still lose money, and the result says that plainly when it is true — including the chance that a run of twenty sessions ends underwater.
- SPX 0DTE only. Same-day expiry: no calendars, no diagonals, no other symbols. The AM-settled monthly root is not ingested, and the pane says so rather than failing quietly on a strategy it cannot price.
What it costs
Building and reading a strategy is free, on any of the 1,122+ finished sessions, with no account — the same terms as the rest of the archive. Testing one over the history spends 10 LAB credits, and a failed run refunds them.
There is no separate subscription for the tester and there will not be one. It shares LAB's credits, so if you already subscribe you have nothing else to buy; if you do not, packs start at $9 and the $49 monthly plan carries 200 credits.
What IS sold in this section is the order ledger: every large SPX order of the session rebuilt from the tape, ranked by what it did to the measured book, and one press from here — the strikes, the rights and the direction load straight into the tester. Finished sessions are free to read; today is the paid half, and the price is on this section's pricing page.
The tester prices structures against history. To journal the SPX fills you actually traded, with the book at the minute each one printed, see FillStub, our options trading journal.