A tour of the main Simula screen: the config toolbar, strategy builder, position type, date range, and advanced settings -- what each section does.
Understanding the Interface
This article is a reference tour of the backtest page -- every control, what it does, and where to learn more about the concept behind it. If you have not run a backtest yet, Your First Backtest is a faster hands-on start; come back here when you want to know what everything else does. There is also an interactive version: the Tutorial button above the Configuration card replays the in-app guided tour.
The backtest page, top to bottom. Every asset page -- stock, forex, or crypto -- uses this same layout.
The Price Chart
The chart at the top shows the asset's recent price history -- a preview of the data your strategy will trade on, before any backtest runs. The range buttons switch between 1Y, 3Y, 5Y, 10Y, and Max views, and the icon buttons toggle between candlestick and line styles. After a run, your results get their own charts -- with your trades marked on them -- in the results section below (see Reading Your Results).
The Configuration Card
The Configuration card frames the test: which direction you trade, on what candle size, over which dates, with how much leverage. Left to right:
Position
Long profits when price rises; Short profits when it falls. One direction per backtest. Long vs Short Strategies explains how the two differ in practice -- they are not mirror images.
Timeframe
The size of each candle, from 1 Minute up to 1 Day. Which intervals are listed depends on the instrument -- forex and crypto offer intraday intervals, while stocks currently trade on daily candles. This single choice controls how often your rules get evaluated and how many candles your date range contains -- Timeframes & Data is worth reading in full.
Leverage
Multiplies both gains and losses. The pills select one or more multipliers (a backtest runs every selected multiplier at once, so you can compare them side by side in the results), and the Custom box accepts a value of your own. Left alone, it tests at 1x -- no leverage. Leverage & Position Sizing covers what leverage does to drawdowns, including total wipeouts.
Fill
When a triggered trade executes. Next open (the default) fills at the next candle's opening price -- the conservative, look-ahead-safe choice, since a live trader can only act after a signal candle closes. Trigger close fills at the triggering candle's own closing price. The Execution timing section of How the Simulation Works explains the trade-off.
Dates
The start and end of the test window. Each button opens a calendar; the start-date calendar has a Select Oldest Date shortcut that jumps to the earliest data available for the asset.
Candles
A live count of how many candles your current timeframe and date range contain, shown against your plan's maximum. More candles means more opportunities for your rules to fire -- and more statistical weight behind the result.
Advanced Settings
The row at the bottom of the Configuration card holds the settings that separate a rough sketch from a realistic simulation:
Commission (%), Spread, Slippage (%)
The three real-world trading costs, all defaulting to zero. Commission is a fee charged on entry and exit; spread is the gap between buying and selling prices; slippage is the difference between the price you expected and the price you got. A backtest with all three at zero simulates a broker that does not exist -- Spreads, Commissions & Slippage shows how much they matter and what values are realistic. (Spread does not apply to stocks, and the field says so there.)
Breakdowns
Toggles Yearly, Monthly, and Daily period-by-period tables in the results. These must be switched on before running -- the Return Breakdown results tab is empty otherwise. See Return Breakdowns.
Monte Carlo
Runs your strategy's trades through hundreds of shuffled simulations to show the range of outcomes luck alone could have produced. When switched On, a Ruin threshold and a Method (Reshuffle or Resample) appear. Start with Monte Carlo: How It Works.
Optimize
Replaces single parameter values with ranges and tests every combination -- Parameter Optimization. A counter shows how many combinations your ranges produce, and the run button changes to Run Optimization. That button stays locked until at least one parameter has a range: with nothing set to vary there is a single combination to test, which is an ordinary backtest. Hover the locked button and it tells you what it is waiting for.
Walk-Forward
The stress test for optimization: repeatedly optimizes on one slice of history and validates on the unseen slice that follows -- Walk-Forward Analysis. Walk-Forward reads its ranges from the same panel Optimize uses, so it needs at least one parameter set to a range as well. Optimize and Walk-Forward cannot both be on at once; enabling one disables the other.
The Strategy Builder
The Strategy Builder card is where the rules live. The Entry Logic column decides when a position opens; the Exit Logic column decides when it closes. Both columns work the same way, and a counter above each shows how many conditions you have used out of your plan's allowance.
Anatomy of a condition
Each condition is a sentence you assemble: IF [indicator] [comparison] [indicator or value]. Piece by piece:
The indicator
Clicking Indicator... opens the Select Technical Indicator dialog -- searchable, organized by category (trend, momentum, volatility, volume, candlestick patterns, and more). Every indicator has its own Learn article; start at the Indicators section if you are choosing your first one.
Its parameters
Most indicators take one or more numbers (an averaging period, a smoothing factor). These appear as small inputs inside the sentence, pre-filled with sensible defaults; hovering one shows its valid range.
The comparison
How the two sides relate: Crossed Over from Below (Golden Cross) and Crossed Under from Above (Dead Cross) fire only on the candle where one line moves through the other; Greater Than and Less Than are true on every candle where the relation holds; Touched (available when comparing price itself) fires when the candle's range intersects a level. The difference between a crossover and a threshold changes a strategy completely -- Entry & Exit Conditions explains why.
The right-hand side
The compare to toggle chooses between another Indicator (e.g. SMA vs SMA) or a fixed Value (e.g. RSI vs 30). If you pair two indicators that live on different scales, the builder warns you the comparison may not be meaningful.
A per-condition timeframe
The small timeframe pill on a condition defaults to Match strategy, but can be set to a higher timeframe -- for example, checking a daily trend inside a 1-hour strategy. That is multi-timeframe analysis, and a badge appears in the card header whenever a strategy uses it.
Candlestick-pattern conditions read differently -- IF [pattern] is detected -- and bidirectional patterns add a signal dropdown (Bullish, Bearish, or Any). See Candlestick Patterns.
Combining conditions: AND, OR, and groups
Add Condition adds another rule to the column, joined to its neighbor by a small AND/OR pill -- click the pill to flip it. AND means both rules must be true on the same candle; OR means either one suffices.
Add Condition Group starts a new bordered group with its own AND/OR logic between groups, which is how you express things like "(trend is up AND momentum confirms) OR (price broke out)". Groups are the parentheses of the strategy builder.
Risk exits: the buttons below Exit Logic
Below the exit conditions sit five buttons that add price-based and time-based safety nets: Add Take Profit, Add Stop Loss, Add Trailing Stop, Add Break-Even Stop, and Add Time Exit. Each adds a one-blank sentence ("Stop loss if lost more than __ %", "Time exit after __ candles") that is always joined to your other exits with OR -- whichever exit triggers first closes the trade. Unlike indicator conditions, stops and take-profits trigger inside a candle the moment its high or low reaches the threshold. Stop-Loss, Take-Profit & Trailing Stops covers all five.
Running a Backtest
The large button at the bottom of the Strategy Builder reads Run Backtest -- or Run Optimization / Run Walk-Forward when those modes are on. While the engine works, a Processing Backtest... overlay asks you not to close the window; when it finishes, the page scrolls to the results. Backtests are free to re-run as often as you like -- changing one setting and re-running is the core workflow.
Saving, Loading & Favorites
Save Strategy (below the Strategy Builder) stores the entire builder state -- conditions, stops, position type -- under a name and optional description. Load Strategy brings any saved strategy back, onto any asset, with search and group filters. The heart button next to the asset name adds the asset to your favorites. Saved strategies, favorites, and your past runs each have their own pages in the sidebar (Strategies, Favorites, Backtest History).
Why some controls show a padlock
Simula's plans differ in caps and features -- condition counts, candles per backtest, intraday timeframes, advanced settings, and more. Anything outside your current plan shows a padlock rather than disappearing, and clicking it tells you which plan includes it. Everything in this article behaves identically once unlocked.