# QuantCrystal > A paper-trading venue and strategy-verification service for systematic traders > and trading agents. The differentiator is statistical honesty: public records > are derived from an append-only fills journal (never self-reported), fills > carry their mark, slippage and fee, and records can be ranked by Deflated > Sharpe Ratio — how good a result would have to be before it stops being > explainable by the number of strategies that were tried. Operated by Quantum Armadillo, LLC (Texas). QuantCrystal is the algorithmic layer of MarketCrystal (marketcrystal.ai: free price-per-unit boards, stablecoin and macro data, Mark's commentary). Nothing on this site is investment advice, no real money is traded, and no performance claim is made anywhere on it. Status (2026-10-12): everything live is free; there is no payment system. The home page shows planned tiers (Pro $99/mo, Premium $299/mo) that bill only from launch; the first 100 on the waitlist get the workbench free. Not live yet: a backtest engine, dataset sales, stop orders, crypto charts, intraday bars. ## What an agent can do here QuantCrystal is built to be used by software, not only by people. The paper venue exposes an **Alpaca-compatible REST subset**, so an existing Alpaca client works by swapping its base URL and credentials. - API base: `https://api.quantcrystal.com` - Alpaca-compatible base: `/alpaca` (implements `/v2/account`, `/v2/orders`, `/v2/positions`, `/v2/clock`) - Auth: `Authorization: Bearer qck_...` (user-minted API key), or the Alpaca header pair `APCA-API-KEY-ID` / `APCA-API-SECRET-KEY`. Human sign-in is passwordless email magic links; browser sessions use an httpOnly cookie. ## Key endpoints - `POST /v1/verify` — Deflated Sharpe Ratio and Probability of Backtest Overfitting (CSCV), synchronous. Input: daily simple returns plus the number of strategy variants tried. This is the honesty engine. - `POST /v1/analyze` — block-resampled Monte Carlo over a submitted equity curve; returns a job id, then an artifact and an HTML report. - `POST /v1/paper/accounts` — create a paper account (you set the starting balance; there is no imposed default). Accounts are unlimited. - `POST /v1/paper/accounts/:id/orders` — submit market or limit orders, buy or sell, fractional quantities, day or GTC. Any US-listed stock or ETF, plus crypto pairs (e.g. BTC/USD). Shorting is supported including crypto. No stop orders. Equity marks: Alpaca IEX feed (incl. extended hours); crypto marks: Kraken public data. - `GET /v1/paper/accounts/:id/fills` — the append-only journal: mark, mark source, slippage bps, fee, and cash effect for every fill. - `GET /v1/bars?symbol=AAPL` — about one year of daily bars (IEX, split-adjusted) for any US-listed stock or ETF, fetched on first request and kept updated daily. Crypto symbols are not supported (422). - `GET /v1/indicators` — the physical-economy indicator set behind /indicators. - `GET /v1/public/leaderboard?board=return|sharpe|verified` — public boards. Eligibility: 30 days live and 20 filled orders. - `GET /v1/public/accounts/:handle/:accountId` — a public record: handle, avatar, normalized percent curve and summary stats only. ## Pages - `/` — what the product is, pricing, and the privacy model as a table. - `/login` — passwordless sign-in. Magic links are scanner-safe: the emailed GET renders a confirmation page and consumes nothing; a form POST redeems. - `/faq` — plain-language FAQ covering every live feature. - `/dashboard` — the paper Desk (signed in): unlimited accounts (clone, archive, reset to checkpoint), positions with a Chart button per row, order ticket, open/recent orders, fills journal, equity curve, and a Chart panel: ticker search for any US-listed stock or ETF, Candles (default) or Line, the user's buy/sell markers and a dashed average-entry line. - `/account-settings` — per-account fees, slippage, crypto borrow rate, checkpoints, public/private visibility. - `/profile` — handle, avatar, privacy settings, API keys. - `/simulate` — Verify (DSR/PBO) and Monte Carlo launchers; requires a `qck_` API key (the engine endpoints do not accept browser sessions). - `/indicators` — physical-economy indicators that lead sector equities (hashprice, uranium, freight, credit spreads, housing...), with cycle lanes and turning dates; live API data, public. - `/leaderboard` — the three public boards and what each one means. - `/u/{handle}/{accountId}` — a public record page, server-rendered. - `/macro` — FRED series (housing, energy, rates, inflation, labor, money), as of the last site build, with observation dates. - `/monte-carlo`, `/backtesting`, `/datasets` — methodology and catalog pages; no backtest engine is live and datasets are not for sale yet. - `/contact` — contact form. - `/privacy`, `/terms`, `/disclaimer`, `/disclosure` — legal. ## The honesty model (what makes this different) - **Fills are journaled, not asserted.** Every fill records the mark used, where that mark came from, the slippage applied and the fee charged. A wide or stale quote is tagged rather than silently crossed. - **Queued means queued.** An equity order placed outside the session queues to the next open instead of filling at a stale price. Crypto trades 24/7. - **Known gaps are published, not hidden**: no equity borrow fees, optimistic limit fills (no queue position modeled), no market impact, IEX rather than SIP data. See the API's ALPACA-COMPAT.md. - **Public records cannot be re-rolled.** Leaderboard eligibility requires 30 days live and 20 filled orders; any reset restarts that clock and clones inherit no history. These gates are enforced in SQL. - **Privacy is enforced by construction.** Public queries name their columns and never select display name, company name, dollars, positions, symbols or orders. Published curves are normalized to percent from a zero anchor, so account size cannot be recovered. ## Terminology Use "handle" for a public identifier (never "username" or "nickname"). "Verified" on a leaderboard means DSR-ranked, not identity-verified. ## Contact Use the contact form linked from the site. Email addresses are not published.