What is One Candle Ahead?

One Candle Ahead is a free trading simulator that lets you practice stock and cryptocurrency trading using real historical market data, one candle at a time. You predict the next move, learn candlestick patterns, and build technical analysis skills without risking real money.

Is One Candle Ahead really free?

Yes. Core gameplay — stock and crypto simulations, leaderboard, candlestick charts — is 100% free. The iOS and Android apps include optional in-app purchases for cosmetic items, but nothing is paywalled.

How do you learn candlestick patterns here?

Every game reveals one candle at a time from a real historical chart. You decide whether to buy, hold, or sell. Over dozens of rounds you internalize the shape of reversals (hammer, engulfing), continuations (marubozu), and indecision (doji) in context — not just from a static chart picture.

What market data does the simulator use?

Real historical OHLCV (open/high/low/close/volume) data for major U.S. stocks (AAPL, MSFT, GOOGL, TSLA, etc.) and top cryptocurrencies (BTC, ETH, SOL). Chart windows are randomized so you can't simply memorize outcomes.

Does One Candle Ahead work on mobile?

Yes. The web app is fully responsive, and native apps are available for iOS (App Store) and Android (Google Play). The mobile apps add 14 achievements, daily challenges, PvP duels, referral rewards, and a seasonal leaderboard.

Will this make me profitable in real trading?

No simulator can guarantee real-market profits. One Candle Ahead trains pattern recognition and disciplined decision-making — two foundations of good trading — but real money involves slippage, fees, news, and emotion. Use it as practice, not a crystal ball.

Do I need an account to play?

No. You can start as a guest. Signing in with Google or Apple saves your balance, leaderboard rank, and achievements across devices.

Methodology & Data Sources

A transparent account of where our market data comes from, how the simulator works under the hood, and what it cannot do.

Data sources

U.S. equities use publicly available end-of-day OHLCV data covering major listings (AAPL, MSFT, GOOGL, AMZN, NVDA, TSLA, META, and similar large-cap names). Crypto candles come from the Binance public REST API and cover BTC, ETH, SOL, and other top-volume pairs. Both feeds refresh nightly. We use only publicly accessible data — no paywalled vendor feeds.

Date ranges and randomization

For each simulator session we pick a random historical window from the dataset so users cannot memorize outcomes. Stock windows go back to 2015 for most symbols; crypto windows cover 2017–present. Date ranges shown to users are the actual historical dates from the raw feed.

Chart rendering

Candles are drawn as native SVG inside React components using the unmodified OHLCV values — no smoothing, repainting, or synthetic candles. Volume bars are scaled to the session high. Indicator overlays (SMA, EMA, RSI, Bollinger Bands, MACD, VWAP) are computed from the same raw OHLCV using textbook formulas.

Simulation mechanics

Users see one candle at a time. A decision (buy / hold / sell / size) is committed before the next candle is revealed. Fills happen at the next candle's open price. We model a basic 0.05% spread on stocks and 0.10% on crypto plus a small flat commission so equity curves do not look unrealistic. Slippage on illiquid moves is not modeled in detail — see Limitations.

Pattern definitions

Candlestick pattern names (hammer, doji, bullish engulfing, shooting star, marubozu, morning star, etc.) follow Steve Nison's "Japanese Candlestick Charting Techniques" as the primary reference, cross-checked against John Murphy's "Technical Analysis of the Financial Markets" where indicators are involved. Where sources disagree, the article explicitly notes the disagreement.

Limitations

The simulator does not model: real-time order book depth, partial fills on size, exchange outages, dividend/split adjustments beyond the source feed, after-hours liquidity for stocks, or maker/taker fee tiers for crypto. Results in the simulator should be interpreted as ordinal practice signal, not as an expected real-money return.

Reporting data errors

If a candle, indicator, or pattern looks wrong, email support@onecandleahead.app with the symbol, date, and what you expected. Confirmed data issues are patched in the next nightly refresh and noted in a public changelog when material.

Last updated

2026-05-07

About us · Editorial policy · Blog · Practice stocks

Educational disclaimer

One Candle Ahead is an educational paper-trading simulator. It does not provide financial advice, investment recommendations, brokerage, exchange services, real-money trading, or guaranteed results.