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

# Constant Local Volatility

> Query a constant local volatility model that returns the same local volatility for any spot and time. Local volatility represents the instantaneous volatility at a specific spot price and time, used in local volatility models for path-dependent exotic option pricing. Simplest case for testing and model validation. [Tier: PRO, Credits: 5]



## OpenAPI

````yaml api-specs/volatility.json post /quantlib/volatility/local-vol/constant
openapi: 3.1.0
info:
  title: FinceptQuantLib API - Volatility
  description: >-
    Volatility module endpoints for FinceptQuantLib API. Standard Tier module (2
    credits per request) providing comprehensive volatility surface modeling,
    SABR model calibration and analytics, and local volatility calculations for
    derivatives pricing and risk management.
  version: 3.0.0
  contact:
    name: Fincept API Support
    url: https://fincept.in
servers:
  - url: https://api.fincept.in
    description: Fincept API Production Server
security:
  - APIKeyHeader: []
tags:
  - name: quantlib-volatility
    description: >-
      Volatility surface modeling, SABR calibration, and local volatility
      calculations
    x-displayName: Volatility
paths:
  /quantlib/volatility/local-vol/constant:
    post:
      tags:
        - quantlib-volatility
      summary: Constant Local Volatility
      description: >-
        Query a constant local volatility model that returns the same local
        volatility for any spot and time. Local volatility represents the
        instantaneous volatility at a specific spot price and time, used in
        local volatility models for path-dependent exotic option pricing.
        Simplest case for testing and model validation. [Tier: PRO, Credits: 5]
      operationId: local_vol_constant
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - volatility
                - spot
                - time
              properties:
                volatility:
                  type: number
                  description: Constant local volatility value (annualized)
                  example: 0.2
                  minimum: 0
                  maximum: 5
                spot:
                  type: number
                  description: >-
                    Spot price for query (not used in constant model but
                    required for interface)
                  example: 100
                  minimum: 0
                time:
                  type: number
                  description: >-
                    Time for query in years (not used in constant model but
                    required for interface)
                  example: 0.5
                  minimum: 0
            example:
              volatility: 0.2
              spot: 100
              time: 0.5
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      local_vol:
                        type: number
                        description: Local volatility at the query point (same as input)
                        example: 0.2
                      spot:
                        type: number
                        description: Spot price (echo of input)
                        example: 100
                      time:
                        type: number
                        description: Time (echo of input)
                        example: 0.5
              example:
                success: true
                data:
                  local_vol: 0.2
                  spot: 100
                  time: 0.5
        '401':
          $ref: '#/components/responses/UnauthorizedError'
        '402':
          $ref: '#/components/responses/InsufficientTierError'
        '422':
          $ref: '#/components/responses/ValidationError'
      security:
        - APIKeyHeader: []
components:
  responses:
    UnauthorizedError:
      description: Authentication information is missing or invalid
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Invalid API key
    InsufficientTierError:
      description: API tier insufficient for this endpoint
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Endpoint requires Standard tier or higher
    ValidationError:
      description: Validation Error
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: array
                items:
                  type: object
                  properties:
                    loc:
                      type: array
                      items:
                        type: string
                    msg:
                      type: string
                    type:
                      type: string
          example:
            detail:
              - loc:
                  - body
                  - volatility
                msg: field required
                type: value_error.missing
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      in: header
      name: X-API-Key
      description: >-
        API key for authentication. Get your key at
        https://api.fincept.in/auth/register

````