Bollinger Bands - Multi Symbol Alert (Miu)

This script extends the classic Bollinger Bands indicator with support for up to 8 user-defined symbols and a unique alert system.
Unlike traditional Bollinger Band indicators, it allows traders to configure alerts across multiple assets without keeping the indicator visible on the chart, making it ideal for passive multi-asset monitoring.

What it does:
This script calculates Bollinger Bands using a 100-period simple moving average and a standard deviation multiplier of 3 (or any input you set in the settings panel).
For each selected symbol, the upper and lower bands are retrieved using request.security() and monitored for breakouts.

Alerts are triggered when the closing price of the selected symbol breaks above the upper band (Overbought) or below the lower band (Oversold) — at the bar close.

How to use it:
1) Add the indicator to your chart.
2) Open the settings panel.
3) Select up to 8 symbols to monitor.
4) After setting parameters, click the three dots next to the indicator title and choose "Add Alert on...".
5) Name your alert and confirm.
6) If you don’t wish to keep the indicator visible, you can remove it from the chart — alerts will still function as expected.

Alert message includes:
- Symbol name (e.g., BTC, ETH, LTC)
- (OB) for overbought or (OS) for oversold
- Symbol’s price at the alert moment

Technical note:
This script uses request.security() to fetch Bollinger Band levels and closing prices from up to 8 selected symbols in real time.

Feel free to leave your feedback or suggestions in the comments section below.

Enjoy!