How to Create Custom Trading Indicators Without Coding

You do not need AI to build a custom indicator in Setup.Cash. The Indicators Lab ships with a small, readable formula language that lets you define exactly what an indicator computes and plots. This guide walks through building one by hand.

The Three Parts of Every Indicator

A custom indicator has three parts:

1. Inputs — the tunable settings (lengths, multipliers, thresholds, source).
2. Outputs — what the indicator produces (lines, levels, and signal events).
3. Source code — the formula that computes the outputs from price.

In the Custom tab of the Indicators Lab you edit all three: a visual list of inputs and outputs, plus a source-code box.

The Formula Language in 2 Minutes

The language is stateless and works on whole price series at once. The building blocks are:

Price series (already available): open, high, low, close, volume, hl2, hlc3, ohlc4. You can also use src("close").

Statements:

• let name = expression — declare a reusable value
• plot("outputKey", expression) — emit a numeric line
• event("outputKey", booleanExpression) — emit a signal event

Functions: sma, ema, rma, wma, rsi, atr, highest, lowest, stdev, roc, zscore, crossover, crossunder, shift, abs, min, max, if, between, and more.

A complete simple indicator looks like this:

let basis = ema(close, len)
plot("value", basis)

That plots an EMA of the close. Every output key you plot or event must also be declared in the outputs list.

Worked Example: An RSI With Bands and Signals

Say you want RSI with overbought/oversold thresholds and crossover signals.

Inputs: len (int, default 14), ob (int, default 70), os (int, default 30), src (source, default close).

Outputs: rsi (series), buy (event), sell (event).

Source:

let r = rsi(src(src), len)
plot("rsi", r)
event("buy", crossover(r, os))
event("sell", crossunder(r, ob))

Click Test and the lab runs it on real candles and draws it on the chart. You will see the RSI line plus the buy/sell events.

Preview, Tune, Save

The right-hand Indicators Lab panel is a chart workspace:

• Pick a symbol, timeframe, and candle count.
• Hit Run Preview to render candles with your indicator overlaid.
• Read the Stats / Output diagnostics to confirm values and signal counts.

Adjust the inputs, re-run, and when you are happy, click Create to save it to your library.

Every Setting Is Exposed

Unlike a black-box indicator, every input you define is editable later. The Indicators Lab shows the full detail of each setting — type, range, default, and options — and lists every output the indicator produces, so you always know exactly what it does.

Using Your Indicator Everywhere

A saved custom indicator works across the platform:

• Reference it by name in text-to-strategy.
• Add it as a Custom Indicator block in the simple builder.
• Wire it into the blueprint builder like any built-in.

Want a Head Start?

If you would rather describe the idea and let the platform write the first version, use the AI Indicator Generator and then refine the formula by hand. Both paths produce the same kind of fully-editable indicator.

Open the Indicators Lab and build your first one — start simple, preview often, and grow it from there.