# Dynamic Zone Bands

`D07-F07-A10` · Technical Indicators → Bands, Envelopes, and Squeezes · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/bands-envelopes-and-squeezes/dynamic-zone-bands/
Agent skill: `npx skills add IslamBaraka90/Fintech-Algorithms-Library` — https://docs.thefintechbuilder.com/guides/agent-skill/

## Install and import

```bash
npm install fintech-algorithms
```

```ts
import { dynamicZoneBands } from "fintech-algorithms/technical-indicators/bands-envelopes-and-squeezes/dynamic-zone-bands";
```

## Signature

```ts
dynamicZoneBands(input)
```

Dynamic Zone Bands: a quantile envelope of close -- the upper band is the `1 - q` quantile of the last `period` closes and the lower band the `q` quantile -- drawn around a simple moving average.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is the required OHLCV array -- each bar carries `timestamp`, `open`, `high`, `low`, `close`, `volume` and an optional `basis`, strictly ordered by timestamp. From `parameters` this topic reads `period` (default 20, integer >= 2), the quantile and moving-average window, and `q` (default 0.2, a finite number between 0 and 0.5 inclusive), the tail fraction. `period` (default 20, integer >= 2) and `multiplier` (default 2, a finite number >= 0) are read and validated by the band family for every topic in it. `multiplier` is not used by this branch. |

## Returns

`TopicResult`

`series` holds `upper`, `lower` and `center`, in that order; `latest` carries the last of each. All three share a warm-up of `period - 1` leading nulls, so `ready_at` is 19 at the default period.

## Warm-up

The first ``period - 1` bars (19 at the default period)` positions are `null`. Quantiles are taken over the sorted window with linear interpolation between neighbouring closes, and emit only once the window is full.

## Errors

- When `parameters.q` is not a finite number, or falls outside 0 to 0.5 — throws Error
- When `parameters.period` is not an integer >= 2 — throws Error
- When a bar is missing open, high, low, close, or volume, or one of them is not a finite number — throws Error

## Complexity

Time `O(n * period * log period)`, space `O(n)`.

## Worked example

Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

### Input

`input`:

```json
{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}
```

### Call

```ts
dynamicZoneBands(input)
```

### Returns

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

```json
{
  "topic_id": "D07-F07-A10",
  "title": "Dynamic Zone Bands",
  "state": "calculated",
  "ready": true,
  "ready_at": 19,
  "series": {
    "upper": [null, null, null, null, null, null],
    "lower": [null, null, null, null, null, null],
    "center": [null, null, null, null, null, null]
  },
  "latest": {
    "upper": 106.046989472,
    "lower": 102.788143482,
    "center": 104.20055051999998
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}
```

## Verification and provenance

Tier: **verified** (via E).

The worked example below is the figure published in this algorithm's article, replayed and asserted by the test suite on every build. The arithmetic cannot drift without the build failing.

Both tiers guarantee the signature. Full explanation: https://docs.thefintechbuilder.com/guides/verification/

Generated from the docs.json payload shipped inside fintech-algorithms@0.13.0.
The signature and parameter list are checked against the compiled implementation at build time,
so a description that contradicts the code fails the build rather than reaching this file.

## Links

- Article (how it works, step by step): https://thefintechbuilder.com/technical-indicators/bands-envelopes-and-squeezes/dynamic-zone-bands/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/bands-envelopes-and-squeezes/dynamic-zone-bands/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt