Custom indicators

The terminal comes with the indicators most traders use, from moving averages to RSI and MACD. When you want something that is not in that list, you write it yourself in Tide, build it into an .eti file and add it to your chart. It then sits in the chart's Indicators list beside the built-in ones and works the same way.

Write it

Open eTrader Code, press + and choose New Indicator. A simple indicator needs no logic at all. This one draws three moving averages over the price:

indicator "Triple EMA" { panel: overlay }
input int a = 8
input int b = 21
input int c = 55
plot ema(close, a) { title: "Fast", color: #3d7bf5 }
plot ema(close, b) { title: "Medium", color: #e8a33d }
plot ema(close, c) { title: "Slow", color: #d0342c }

That is the whole file. Each plot takes a series and draws it. Each input becomes a setting you can change on the chart later, without opening the code again.

Its own pane

panel: overlay draws on the price chart. For an oscillator, use panel: separate to give it a pane of its own under the chart, and set the scale:

indicator "RSI with bands" {
  panel: separate
  scale: fixed(0, 100)
}
input int length = 14
plot rsi(close, length) { title: "RSI" }
hline(70) { style: dashed }
hline(30) { style: dashed }

A plot can be a line, a histogram, columns, dots, an area and more, and its colour can change with the value, for example red above 70 and green below 30. The Tide manual lists every style, and every one of the built-in indicator functions you can plot, such as bands, macd, atr and ichimoku.

When the Problems tab is clean, press Build. eTrader Code downloads the .eti file.

Add it to the terminal

In eTrader Web, sign in to your trading account and press Indicators on the chart toolbar. Your own indicators come first, under Custom.

1. Press Upload Indicator beside the Custom heading.
2. Pick the .eti file. Only .eti files are accepted, up to 4 MB each, and you can pick several at once.
3. Flip the switch on the indicator's row to put it on the chart.

It then works like a built-in one, with the same eye to hide it and the same settings sheet. Its Inputs tab is built from the inputs you declared. Its Style tab lets you recolour, thicken, restyle or hide any line it draws, without touching the code.

Flip the switch off to take it off the chart. The bin button on the row deletes the indicator. It comes off every chart using it, and this cannot be undone.

Your indicators belong to the trading account, so they are there when you sign in to the same account on another computer.

A new version

Change the code, build again and upload the new file the same way. The terminal sees that you already hold that indicator and updates it in place, keeping your settings.

Where it runs

An indicator runs on your chart, on your own computer, in eTrader Web. That has two consequences worth knowing.

• It never trades. Placing orders is what a bot is for. A bot can read your indicator's values if you write it to, and run in the cloud.
• It cannot reach the internet. An indicator works only with the prices on the chart.

When a plot is not enough

For logic a single expression cannot hold, an indicator can have an onCalculate handler that fills its values candle by candle, and an onChartEvent handler that reacts to a click or a key press on the chart. It can also draw objects, such as trendlines, rectangles, arrows and labels, and put a small panel of values and buttons in a corner of the chart. Start with plots. Most indicators never need more.