# Envelope (ENVELOPE)

> QuantNexus indicator page for the generic price envelope.

**Route**: `/quantnexus/indicators/envelope/`

## What It Does

ENVELOPE builds upper and lower percentage bands around a moving average. It is one of the simplest dynamic channel indicators.

## Formula

`Envelope = MA +/- perc%`

## Parameters

- `perc` - default `2.5`

## C++23 API

```cpp
#include <nonabt/indicators/envelope.hpp>
auto envelope = std::make_unique<nonabt::ENVELOPE>(data().close(), 2.5);
```

## Common Usage

- Use ENVELOPE for breakout and pullback logic.
- Combine it with trend filters.
- Good for coarse support/resistance mapping.

## Practical Pattern

If price consistently trades above the upper envelope, the trend may be stronger than average.