> ## Documentation Index
> Fetch the complete documentation index at: https://docs.backquant.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Changelog

> Returns the v2 release log plus the lifecycle status of v1. Customers integrating against either version use this to decide when to schedule re-integration work — `breaking: true` on any release is the signal to test, and `v1_status` flips to `deprecated` / `sunset` long before v1 is ever turned off.

Response is static — no I/O, sub-millisecond — so polling it from a CI job daily is free.

Static release log with per-version `breaking` flags. Customers integrating against the API use this to decide when to schedule re-integration work - `breaking: true` on any release is the signal to test.


## OpenAPI

````yaml GET /changelog
openapi: 3.1.0
info:
  title: BackQuant API v2
  description: >-

    # BackQuant API v2


    Options + gamma-exposure focused public API. Built on the same data the

    BackQuant Pro Terminal renders — pre-computed every 30s, served from cache.


    ## What's in v2


    * **Discovery**: `/v2/symbols` (universe + per-symbol freshness + supported
      endpoint list), `/v2/expiries` (active expiry tokens with DTE), `/v2/status`
      (per-symbol-per-category health with thresholds + overall classification).
    * **GEX**: composable levels (HVL / call wall / put support / max-pain /
      expected move / gamma-flip zones), strike profile with typed expiry
      filter, expiry profile, strike × expiry heatmap with downsampling,
      greek time-heatmap with DTE/OI/IV filters, history (cursor-paginated),
      Postgres-backed stress history, **per-expiry max-pain with pain curve**.
    * **Options**: filtered options chain with two-layer projection (top-level
      `?fields=` and per-contract `?include=oi,iv,greeks,bid_ask,volume,gex`)
      plus moneyness filter (`?moneyness_min=0.9&moneyness_max=1.1`), expiry
      summary table, full IV suite (surface / term structure / 25Δ-10Δ skew /
      curves / **single-expiry smile** / IV-RV history / VRP), expected move,
      **Breeden-Litzenberger probability density and surface**, typed greek
      profiles (delta / theta / vanna / charm / vega), strike × time charm/vega
      surfaces, strike × expiry 3D greek surface, OI by expiry + history,
      put/call ratio (intraday or daily), 0DTE & weekly premium tide,
      dated-futures term structure.
    * **Liquidation**: heatmap + leverage-tiered distribution.

    * **Multi**: `/v2/multi/gex/levels` — bundled multi-symbol read across the
      universe in one round-trip, with the same `?include=` model as the
      single-symbol endpoint.

    ## Authentication


    Every v2 route (except `/v2/openapi.json`, `/v2/docs`, `/v2/redoc`, and

    `/v2/health`) requires the `X-API-Key` header.


    ```

    X-API-Key: bq_live_your_api_key_here

    ```


    **Get your API key at
    [backquant.com/api-access](https://backquant.com/api-access).**


    The same key works across v1 and v2 — if you already have a v1 key, no

    re-issuance is needed.


    ## Rate limits


    Per-key, derived from your subscription tier:


    | Tier        | Limit                |

    |-------------|----------------------|

    | Monthly     | 60 requests/min      |

    | Yearly      | 120 requests/min     |

    | Enterprise  | No limit             |


    Headers `X-RateLimit-Limit / -Remaining / -Reset` are included in every

    response, and the same triple is echoed inside `meta.rate_limit` when

    populated by middleware.


    ## Response envelope


    ```json

    {
      "success": true,
      "data": { ... },
      "meta": {
        "version": "2.0",
        "timestamp": "2026-04-29T12:00:00.000Z",
        "request_id": "req_…",
        "symbol": "BTCUSDT",
        "spot_price": 67213.5,
        "computed_at": "2026-04-29T11:59:48.000Z",
        "freshness_seconds": 12.0,
        "source": ["deribit","bybit","okx","binance"],
        "exchanges_filtered": ["deribit","bybit"]
      }
    }

    ```


    ## Errors


    ```json

    {
      "success": false,
      "error": {
        "code": "NOT_FOUND",
        "message": "No data for BTCUSDT"
      },
      "meta": { "version": "2.0", "timestamp": "..." }
    }

    ```


    | Code                  | When |

    |-----------------------|------|

    | `UNAUTHORIZED`        | Missing or invalid API key |

    | `FORBIDDEN`           | Subscription doesn't allow API access |

    | `NOT_FOUND`           | Symbol/expiry/etc. not present in cache |

    | `VALIDATION_ERROR`    | Bad query parameters |

    | `RATE_LIMIT_EXCEEDED` | Per-tier limit hit |

    | `UPSTREAM_ERROR`      | Cache or DB temporarily unreachable |

    | `INTERNAL_ERROR`      | Anything else |
        
  version: 2.0.0
servers: []
security: []
tags:
  - name: Meta
    description: Unauthenticated metadata + endpoint catalog (planning your integration)
  - name: Discovery
    description: Symbol catalog, active expiries, and service status
  - name: GEX
    description: Gamma exposure analytics
  - name: Options
    description: Options chain, IV, greeks, probability, premium tide
  - name: Liquidation
    description: Liquidation heatmap and distribution
  - name: Multi
    description: Bundled multi-symbol endpoints (single round-trip across the universe)
paths:
  /changelog:
    get:
      tags:
        - Meta
      summary: API version history with breaking-change flags
      description: >-
        Returns the v2 release log plus the lifecycle status of v1. Customers
        integrating against either version use this to decide when to schedule
        re-integration work — `breaking: true` on any release is the signal to
        test, and `v1_status` flips to `deprecated` / `sunset` long before v1 is
        ever turned off.


        Response is static — no I/O, sub-millisecond — so polling it from a CI
        job daily is free.
      operationId: get_changelog_changelog_get
      parameters:
        - name: X-API-Key
          in: header
          required: false
          schema:
            anyOf:
              - type: string
              - type: 'null'
            title: X-Api-Key
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ChangelogResponse'
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/V2ErrorEnvelope'
          description: Unauthorized
        '404':
          description: No data available for the requested resource
          content:
            application/json:
              example:
                success: false
                error:
                  code: NOT_FOUND
                  message: No data for BTCUSDT
                meta:
                  version: '2.0'
                  timestamp: '2026-04-29T12:00:00Z'
        '422':
          description: Validation error on query parameters
          content:
            application/json:
              example:
                success: false
                error:
                  code: VALIDATION_ERROR
                  message: Invalid request parameters
                  details:
                    errors: []
                meta:
                  version: '2.0'
                  timestamp: '2026-04-29T12:00:00Z'
        '429':
          description: Rate limit exceeded
          content:
            application/json:
              example:
                success: false
                error:
                  code: RATE_LIMIT_EXCEEDED
                  message: Rate limit exceeded. Try again later.
                meta:
                  version: '2.0'
                  timestamp: '2026-04-29T12:00:00Z'
      security:
        - ApiKeyAuth: []
components:
  schemas:
    ChangelogResponse:
      properties:
        success:
          type: boolean
          const: true
          title: Success
          default: true
        data:
          $ref: '#/components/schemas/ChangelogData'
        meta:
          $ref: '#/components/schemas/V2Meta'
      type: object
      required:
        - data
        - meta
      title: ChangelogResponse
    V2ErrorEnvelope:
      properties:
        success:
          type: boolean
          const: false
          title: Success
          default: false
        error:
          $ref: '#/components/schemas/V2Error'
        meta:
          $ref: '#/components/schemas/V2Meta'
      type: object
      required:
        - error
        - meta
      title: V2ErrorEnvelope
      description: Returned for every non-2xx response.
    ChangelogData:
      properties:
        current_version:
          type: string
          title: Current Version
        v1_status:
          type: string
          enum:
            - stable
            - deprecated
            - sunset
          title: V1 Status
          description: >-
            Lifecycle status of the v1 API. `stable` = fully supported
            indefinitely. `deprecated` = still serving but no new features;
            migrate to v2. `sunset` = scheduled removal date in changes[].
        releases:
          items:
            $ref: '#/components/schemas/ChangelogEntry'
          type: array
          title: Releases
        docs_url:
          type: string
          title: Docs Url
          default: /v2/docs
        openapi_url:
          type: string
          title: Openapi Url
          default: /v2/openapi.json
      type: object
      required:
        - current_version
        - v1_status
        - releases
      title: ChangelogData
    V2Meta:
      properties:
        version:
          type: string
          const: '2.0'
          title: Version
          description: API version tag.
        timestamp:
          type: string
          title: Timestamp
          description: ISO 8601 wall-clock when the response was built.
        request_id:
          anyOf:
            - type: string
            - type: 'null'
          title: Request Id
          description: X-Request-ID for tracing across logs / Sentry.
        symbol:
          anyOf:
            - type: string
            - type: 'null'
          title: Symbol
          description: Symbol the response is about, if applicable.
        spot_price:
          anyOf:
            - type: number
            - type: 'null'
          title: Spot Price
          description: Current spot price for the symbol.
        computed_at:
          anyOf:
            - type: string
            - type: 'null'
          title: Computed At
          description: ISO 8601 of when the underlying cache value was last written.
        freshness_seconds:
          anyOf:
            - type: number
            - type: 'null'
          title: Freshness Seconds
          description: '`now - computed_at` in seconds; useful for staleness alarms.'
        source:
          anyOf:
            - items:
                type: string
              type: array
            - type: 'null'
          title: Source
          description: Upstream venue list the data flowed through.
        exchanges_filtered:
          anyOf:
            - items:
                type: string
              type: array
            - type: 'null'
          title: Exchanges Filtered
          description: Echo of the `?exchanges=` filter when one was applied.
        rate_limit:
          anyOf:
            - additionalProperties: true
              type: object
            - type: 'null'
          title: Rate Limit
          description: '`{limit, remaining, reset}` echo of the rate-limit headers.'
        extra:
          anyOf:
            - additionalProperties: true
              type: object
            - type: 'null'
          title: Extra
          description: Open dict for endpoint-specific metadata (filter_hash, etc.).
      type: object
      required:
        - version
        - timestamp
      title: V2Meta
      description: |-
        The meta block returned alongside every v2 response.

        Every field after `version`/`timestamp` is optional because endpoints
        attach different combinations — e.g. `/v2/status` skips `symbol`, the
        chain endpoint sets `extra.filter_hash`, etc. Listing them here means
        SDKs get a typed accessor for each instead of a generic `meta: dict`.
    V2Error:
      properties:
        code:
          type: string
          title: Code
          description: Stable machine-readable error code (see /v2/meta).
        message:
          type: string
          title: Message
          description: Human-readable description.
        details:
          anyOf:
            - additionalProperties: true
              type: object
            - type: 'null'
          title: Details
          description: >-
            Optional structured payload — e.g. validation_error returns the
            failing field list.
      type: object
      required:
        - code
        - message
      title: V2Error
    ChangelogEntry:
      properties:
        version:
          type: string
          title: Version
        released_at:
          type: string
          title: Released At
          description: ISO date.
        breaking:
          type: boolean
          title: Breaking
          description: True if any change in this release breaks existing client code.
          default: false
        summary:
          type: string
          title: Summary
        changes:
          items:
            type: string
          type: array
          title: Changes
          default: []
      type: object
      required:
        - version
        - released_at
        - summary
      title: ChangelogEntry
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: Your BackQuant API key (same key as v1)

````