---
title: "Api V2 Market Volatility Get"
method: GET
path: "/api/v2/market/volatility"
tags: ["Market Data (v2)"]
---

# Api V2 Market Volatility Get

`GET /api/v2/market/volatility`

## Request

- Base URL: `https://api.zerogex.io` (the document declares no server; this is the origin it was published from)
- URL: `https://api.zerogex.io/api/v2/market/volatility`
- Auth: HTTP bearer

Returns volatility-index metrics as two scored dimensions, for either
the CBOE S&P 500 Volatility Index (``ticker=VIX``, default) or the CBOE
Nasdaq-100 Volatility Index (``ticker=VXN``).

**Level** — *where is the index right now?*
Maps the current reading to a 0–10 log scale anchored to historical
percentiles:
- `0–2`  → Subdued  (~10–15, historically quiet)
- `2–4`  → Low      (~15–19, below-average vol)
- `4–6`  → Moderate (~19–27, near long-run average)
- `6–8`  → Elevated (~27–38, above-average fear)
- `8–10` → Extreme  (~38+, crisis-level fear)

**Momentum** — *which direction and how fast is the index moving?*
Weighted composite rate-of-change across five time scales (5 min through
2 hrs), normalised against realised per-bar volatility of the index.

**Data source** — reads the rolling 5-min bar window maintained by the
per-ticker streaming ingester (VIX → ``vix_bars``, VXN → ``vxn_bars``).

## Query parameters

- `ticker` 'VIX' | 'VXN': Volatility index to score: 'VIX' ($VIX.X) or 'VXN' ($VXN.X).

## Response `200`

Successful Response

- EnvelopeVolatilityIndexResponse
  - `data` VolatilityIndexResponse, required
    - `timestamp` string, date-time, required: Timestamp of the latest bar (ET)
    - `index` number, required: Current index close (e.g. $VIX.X or $VXN.X)
    - `level` number, required: Index level mapped to 0–10 (log scale). 0 = ultra-calm (~10), 5 = ~25, 10 = extreme fear (~50+).
    - `level_label` string, required: Human-readable label: Subdued / Low / Moderate / Elevated / Extreme
    - `momentum` number, required: Index rate-of-change mapped to 0–10 (±4σ range). 0 = collapsing, 5 = stable, 10 = surging.
    - `momentum_label` string, required: Human-readable label: Collapsing / Easing / Stable / Rising / Surging
    - `cache_bars` integer, required: 5-min bars used from the per-ticker bars table for this response
    - `latest_bars` VolatilityBar[]: Most-recent 10 bars for debugging / charting
      - `timestamp` string, date-time, required
      - `close` number, required
  - `freshness` Freshness, required: The v2 freshness envelope. Present on every ``/api/v2/*`` response.
    - `evaluated_at` string, date-time, required: When the API evaluated this response (server wall clock, UTC). Endpoint-health signal: advances on every request even when the underlying data is unchanged.
    - `generated_at` string, date-time, required: When the served data was computed. Equals the snapshot stamp for cycle-backed endpoints, or evaluated_at for endpoints computed on demand for this request.
    - `source_timestamp` string, date-time, nullable: Timestamp of the upstream market observation the payload derives from. This is what freshness_status is measured against. Null when the endpoint has no upstream feed or returned no rows.
    - `latest_event_at` string, date-time, nullable: Newest event timestamp present in the payload (last bar, last trade, last scored row). Best-effort on very large responses, which are sampled rather than fully walked.
    - `age_seconds` number, nullable: evaluated_at - source_timestamp, in seconds. Null when source_timestamp is null.
    - `market_session_status` string, required: pre-market | regular | after-hours | closed (US/Eastern).
    - `expected_update_cadence` string, nullable: ISO-8601 duration for how often this endpoint's data is expected to change right now, e.g. PT60S. Null means no updates are expected (weekend, holiday, or a feed that only runs during the session).
    - `expected_update_cadence_seconds` number, nullable: expected_update_cadence as a number of seconds.
    - `cadence_profile` string, required: Identifier of the cadence class this endpoint belongs to, e.g. analytics_cycle. Stable across releases; the seconds behind it may be retuned.
    - `stale_after` string, date-time, nullable: Instant after which this payload should be treated as stale. Null whenever expected_update_cadence is null.
    - `freshness_status` 'fresh' | 'aging' | 'stale' | 'session_closed' | 'static' | 'unknown', required: The rolled-up freshness verdict for one response. ``fresh`` ``source_timestamp`` is within one expected update cadence. ``aging`` Past one cadence but not yet past ``stale_after`` — the grace band that absorbs normal cycle jitter. Not an error; a client that polls faster than the cadence sees this routinely. ``stale`` Past ``stale_after`` while updates *were* expected. This is the actionable state: the feed behind this endpoint is late. ``session_closed`` A feed-backed endpoint whose feed is not due to produce anything right now (weekend, holiday, or a feed that only runs during the session). The payload is the last good value — deliberately NOT reported as ``stale``, because an overnight consumer polling a closed market is not observing a fault and should not page on it. ``static`` The endpoint is not feed-backed at all: completed history, or a result computed from the caller's own inputs. Age here carries no health meaning and never becomes a fault. ``unknown`` No source timestamp could be resolved from the payload (e.g. a pure calculator, an admin endpoint, or an empty result set). A consumer should fall back to ``evaluated_at`` for endpoint health and make no claim about data age.

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/zerogex/apis/zerogex-api.md) · [All operations](https://skmtc.dev/zerogex/apis/zerogex-api/llms.txt) · [OpenAPI document](https://skmtc.dev/zerogex/apis/zerogex-api/revisions/753b26bf0592?raw)