---
title: "Api V2 Forced-Flow Session-Surface Get"
method: GET
path: "/api/v2/forced-flow/session-surface"
tags: ["Forced Flow (v2)"]
---

# Api V2 Forced-Flow Session-Surface Get

`GET /api/v2/forced-flow/session-surface`

## 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/forced-flow/session-surface`
- Auth: HTTP bearer

Full-session forced-flow field: the ACTUAL historical field recomputed from
stored ``option_chains`` (RTH open -> now) plus a projection of the current
book (now -> close).

Columns march left (open) to right (close); ``now_index`` marks the boundary
between recorded history and projection. History is rebuilt from
``option_chains`` because the persisted ``forced_flow_profile.profile`` JSONB
is written empty -- so the past field cannot be read back, only recomputed.

## Query parameters

- `symbol` string
- `spot_range_pct` number
- `past_steps` integer: Actual-history columns
- `future_steps` integer: Projection columns to close
- `expiry` string, nullable

## Response `200`

Successful Response

- EnvelopeSessionSurfaceResponse
  - `data` SessionSurfaceResponse, required
    - `symbol` string, required
    - `spot` number, required
    - `timestamp` string, date-time, required
    - `session_open_min_to_close` number, required
    - `now_min_to_close` number, required
    - `prices` number[], required
    - `z` array[], required
      - number[]
    - `columns` SessionColumnOut[], required
      - `min_to_close` number, required
      - `spot` number, required
      - `magnet` number, nullable
      - `pivot` number, nullable
      - `is_past` boolean, required
    - `now_index` integer, required
    - `price_bars` SessionPriceBar[]
      - `min_to_close` number, required
      - `open` number, required
      - `high` number, required
      - `low` number, 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)