Pine Script Basics

Pine Script is the programming language built into TradingView. It lets traders write their own indicators, test simple strategies directly on charts and create alerts that fire when conditions are met. Pine is designed for one job, calculating values bar by bar on price data, so it is much simpler than a general language like Python. A useful indicator can be just a few lines. Its limits are just as clear: it runs only on TradingView, cannot place orders directly with most brokers and its built in backtester makes simplifying assumptions.

How Pine Script thinks#

Pine runs your script once for every bar on the chart, from the oldest to the newest. Variables like close are series: they hold a value for every bar, and close[1] refers to the previous bar's close. On the live bar, the script recalculates on each price update until the bar closes.

A first indicator#

//@version=6
indicator("Two moving averages", overlay=true)
fastLen = input.int(20, "Fast length")
slowLen = input.int(50, "Slow length")
fast = ta.sma(close, fastLen)
slow = ta.sma(close, slowLen)
plot(fast, "Fast", color=color.teal)
plot(slow, "Slow", color=color.orange)

The ta namespace holds built in technical analysis functions such as ta.sma, ta.ema, ta.rsi and ta.atr. See Moving Averages Explained and RSI (Relative Strength Index).

A simple strategy#

//@version=6
strategy("SMA crossover", overlay=true, initial_capital=10000,
     commission_type=strategy.commission.percent, commission_value=0.05)
fast = ta.sma(close, 20)
slow = ta.sma(close, 50)
if ta.crossover(fast, slow)
    strategy.entry("Long", strategy.long)
if ta.crossunder(fast, slow)
    strategy.close("Long")

By default, strategy orders are evaluated at the bar close and filled at the next bar's open, which avoids the most obvious look ahead error. Set commissions and slippage in the declaration so results are not flattering. See Costs and Slippage in Backtests.

Adding alerts#

alertcondition(ta.crossover(fast, slow), "Bullish cross", "Fast SMA crossed above slow SMA")

Alerts can notify you by app, email or webhook. Webhooks can forward signals to an execution service or your own server. See Alerts and Webhooks.

Repainting#

A script repaints when its historical signals differ from what it would have shown in real time. Common causes:

• Higher timeframe data used without proper offsetting.
• Signals on the unfinished live bar that disappear before close.
• Functions that look forward, such as some pivot calculations that confirm only after later bars.

Repainting indicators make charts look far more accurate than they ever were live. Check by watching an indicator in real time or using bar replay. See TradingView.

Limits of Pine Script#

For research across many symbols or complex portfolios, Python is more flexible. See Python for Trading.

Frequently asked questions#

What is Pine Script used for?#

Writing custom indicators, testing simple strategies and creating alerts on TradingView charts.

Is Pine Script hard to learn?#

It is one of the easier trading languages, with simple syntax and built in indicator functions, though avoiding repainting takes care.

Can Pine Script place real trades?#

Not directly in most cases. Alerts can send webhooks to services or your own code that place orders, and some brokers integrate with TradingView for chart trading.

Next, put the pieces together in Building Trading Bots.