---
title: "Api V2 Signals Basic Vanna-Charm-Flow Get"
method: GET
path: "/api/v2/signals/basic/vanna-charm-flow"
tags: ["Trade Signals (v2)"]
---

# Api V2 Signals Basic Vanna-Charm-Flow Get

`GET /api/v2/signals/basic/vanna-charm-flow`

## 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/signals/basic/vanna-charm-flow`
- Auth: HTTP bearer

Second-order greek dealer-hedging pressure (vanna + charm).

Answers: *which way is the modeled dealer book likely being pulled to
hedge right now from IV moves and time decay, independently of spot?*

- **Vanna** (dVega/dSpot) — dealer delta changes when IV moves. A
  morning IV drop tends to make a book modeled short vanna buy
  underlying (the "vol-crush rally"); direction depends on the book's
  composition and ownership.
- **Charm** (dDelta/dTime) — decay of short-dated deltas toward expiry.
  In the final ~2h, where the modeled book is short calls above spot,
  that decay tends to pull hedging toward selling — which can
  accelerate afternoon drift. Modeled pressure, not a scheduled order.

**Logic highlights** (`src/signals/basic/vanna_charm_flow.py`):
- Sum `dealer_vanna_exposure` + `dealer_charm_exposure × charm_amplification`
  across all strikes in `gex_by_strike`.
- `charm_amplification` — 1.0 most of the day, ramps to 1.5 in the final
  ~40% of the session (charm flow dominates into the close).
- `score = clip(combined / vc_norm, [-1, 1])`; `vc_norm` defaults to 5e7
  (may be scaled per symbol via `normalizers`).
- **Abstains (score=0)** if `gex_by_strike` is empty.
- Legacy rows (no dealer columns) fall back to negated market-aggregate
  exposures — signal still valid, less precise.

**Sign convention:** `+` score = dealer buying pressure (bullish tailwind);
`−` score = dealer selling pressure (bearish headwind).

**Params:**
- `symbol` (default `SPY`). Returns 404 if no row exists yet.

**Returns:**
```json
{
  "underlying": "SPY", "timestamp": "...",
  "clamped_score": 0.42, "score": 42.0, "direction": "bullish",
  "weighted_score": 0.0, "weight": 0.0,
  "vanna_total": 18500000.0,
  "charm_total": 9200000.0,
  "charm_amplification": 1.18,
  "source": "dealer_exposure",
  "context_values": {
    "vanna_total": 18500000.0, "charm_total": 9200000.0,
    "charm_amplification": 1.18, "vc_norm": 50000000.0,
    "source": "dealer_exposure"
  },
  "score_history": [{"score": 31.2, "timestamp": "..."}, "...up to 90"]
}
```

- `score` / `clamped_score` — `[-100, +100]` / `[-1, +1]`; `+` = bullish.
- `vanna_total` — sum of dealer vanna exposure; `+` = dealer delta grows with spot ↑.
- `charm_total` — sum of dealer charm exposure; `+` = dealer delta grows with time.
- `charm_amplification` — `[1.0, 1.5]`; session-time multiplier. `1.5` = final 40%.
- `source` — `"dealer_exposure"` | `"market_exposure_negated"` (legacy fallback) | `"unavailable"`.
- `context_values` — the above plus `vc_norm` (saturation denominator).
- `score_history` — up to 90 recent points.

**Trader interpretation.**
- `score > +40` in the morning → vanna-driven melt-up; trend-follow upside.
- `score < −40` in the final 90 minutes → charm-driven afternoon fade; momentum shorts.
- Crosses zero into the afternoon → pressure reversal; trim directional size.
- `charm_amplification = 1.5` means we're in the EOD acceleration window.
- `source = "market_exposure_negated"` → lower-precision fallback; widen thresholds.

**Page design.** Two stacked horizontal bars: `vanna_total` and
`charm_total × charm_amplification`, colored by sign. A small clock gauge
shows `charm_amplification` on a 1.0→1.5 scale as "time pressure."
Composite `score` as a big number + direction chip on top. Source chip in footer.

## Query parameters

- `symbol` string

## Response `200`

Successful Response

- EnvelopeAny
  - `data` unknown, 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

---

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