> ## 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.

# SABR Smile Dynamics

> Analyze SABR smile dynamics under forward price movements. Calculates sticky-strike volatility (vol remains constant at each strike) and sticky-delta volatility (vol moves with the option's delta) for a shifted forward. Essential for hedging volatility exposure and understanding how the smile evolves with underlying price changes. [Tier: PRO, Credits: 5]



## OpenAPI

````yaml api-specs/volatility.json post /quantlib/volatility/sabr/dynamics
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/sabr/dynamics:
    post:
      tags:
        - quantlib-volatility
      summary: SABR Smile Dynamics
      description: >-
        Analyze SABR smile dynamics under forward price movements. Calculates
        sticky-strike volatility (vol remains constant at each strike) and
        sticky-delta volatility (vol moves with the option's delta) for a
        shifted forward. Essential for hedging volatility exposure and
        understanding how the smile evolves with underlying price changes.
        [Tier: PRO, Credits: 5]
      operationId: sabr_dynamics
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - forward
                - expiry
                - alpha
                - beta
                - rho
                - nu
                - strike
              properties:
                forward:
                  type: number
                  description: Current forward price of the underlying
                  example: 100
                  minimum: 0
                expiry:
                  type: number
                  description: Time to expiry in years
                  example: 1
                  minimum: 0
                alpha:
                  type: number
                  description: SABR alpha parameter
                  example: 0.25
                  minimum: 0
                beta:
                  type: number
                  description: SABR beta parameter
                  example: 0.5
                  minimum: 0
                  maximum: 1
                rho:
                  type: number
                  description: SABR rho parameter
                  example: -0.2
                  minimum: -1
                  maximum: 1
                nu:
                  type: number
                  description: SABR nu parameter
                  example: 0.3
                  minimum: 0
                strike:
                  type: number
                  description: Strike price for volatility evaluation
                  example: 100
                  minimum: 0
                forward_shift:
                  type: number
                  description: >-
                    Change in forward price (e.g., 0.01 for +1 unit, -0.01 for
                    -1 unit)
                  default: 0.01
                  example: 1
            example:
              forward: 100
              expiry: 1
              alpha: 0.25
              beta: 0.5
              rho: -0.2
              nu: 0.3
              strike: 100
              forward_shift: 1
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      sticky_strike_vol:
                        type: number
                        description: >-
                          Volatility at the strike assuming sticky-strike
                          dynamics (vol unchanged at each strike)
                        example: 0.25
                      sticky_delta_vol:
                        type: number
                        description: >-
                          Volatility assuming sticky-delta dynamics (vol follows
                          option delta)
                        example: 0.2485
                      forward_shift:
                        type: number
                        description: Forward price shift applied (echo of input)
                        example: 1
              example:
                success: true
                data:
                  sticky_strike_vol: 0.25
                  sticky_delta_vol: 0.2485
                  forward_shift: 1
        '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

````