---
title: mass_index (MASS Index)
description: Volatility indicator. Standard math aligned with TradingView Pine Script.
---

# `mass_index` — MASS Index

> Category: **Volatility** · Composite

::: tip For Skill / AI Agent integrations
When you `POST /api/indicators?explain=true`, the response carries a `knowledge` block with this indicator's interpretation rubric. **Pass it to your LLM together with the numeric data** — don't make the LLM guess thresholds from memory. Full rubric lives at the [Chinese page](https://docs.mobiusquant.ai/zh/indicators/mass_index) (summary_focus / signals / caveats).
:::

This is a volatility indicator.
Math is aligned with TradingView Pine Script.

## Parameters

| Parameter | Type | Default |
|------|------|--------|
| `ema_length` | int | `9` |
| `length` | int | `10` |

## Output columns

| Column |
|------|
| `mi` |

## Example call

```bash
curl -X POST -H "Authorization: Bearer mq_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "exchange": "binance",
    "market":   "perp",
    "symbol":   "BTCUSDT",
    "interval": "5m",
    "limit":    100,
    "calc":     [{"name": "mass_index", "params": {"ema_length": 9, "length": 10}}]
  }' \
  https://api.mobiusquant.ai/api/indicators
```

## Full interpretation guide

The full description, signal interpretation, caveats and analysis focus points are
documented in Chinese at:

[mass_index (中文详情)](https://docs.mobiusquant.ai/zh/indicators/mass_index)

## Related indicators

[atr](./atr) · [bollinger](./bollinger) · [chande_kroll_stop](./chande_kroll_stop) · [donchian_channels](./donchian_channels) · [fibonacci_bollinger_bands](./fibonacci_bollinger_bands) · [historical_volatility](./historical_volatility) · [keltner_channels](./keltner_channels) · [linear_regression_channel](./linear_regression_channel)

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