> ## 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.

# Short Rate Bond Pricing

> Calculate zero-coupon bond prices using short rate models (Vasicek, CIR, or Hull-White). These models describe the evolution of interest rates and are fundamental for pricing interest rate derivatives and fixed income securities. Use this endpoint to price bonds at multiple maturities simultaneously for yield curve construction or bond portfolio valuation. [Tier: ENTERPRISE, Credits: 10]



## OpenAPI

````yaml api-specs/models.json post /quantlib/models/short-rate/bond-price
openapi: 3.1.0
info:
  title: FinceptQuantLib API - Models
  description: >-
    Advanced financial modeling module for short rate models, stochastic
    volatility, jump-diffusion processes, and local volatility models. Pro Tier
    required (5 credits per request).
  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-models
    description: >-
      Advanced financial modeling including short rate models, stochastic
      volatility, jump-diffusion, and local volatility models
    x-displayName: Models
paths:
  /quantlib/models/short-rate/bond-price:
    post:
      tags:
        - quantlib-models
      summary: Short Rate Bond Pricing
      description: >-
        Calculate zero-coupon bond prices using short rate models (Vasicek, CIR,
        or Hull-White). These models describe the evolution of interest rates
        and are fundamental for pricing interest rate derivatives and fixed
        income securities. Use this endpoint to price bonds at multiple
        maturities simultaneously for yield curve construction or bond portfolio
        valuation. [Tier: ENTERPRISE, Credits: 10]
      operationId: short_rate_bond
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - maturities
              properties:
                model:
                  type: string
                  enum:
                    - vasicek
                    - cir
                    - hull_white
                  default: vasicek
                  description: >-
                    Short rate model to use. Vasicek allows negative rates, CIR
                    ensures positive rates, Hull-White fits an initial term
                    structure
                kappa:
                  type: number
                  default: 0.1
                  description: >-
                    Mean reversion speed (annualized). Higher values mean faster
                    reversion to long-term rate. Typical range: 0.01-0.5
                theta:
                  type: number
                  default: 0.05
                  description: >-
                    Long-term mean rate (annualized). The rate towards which the
                    short rate reverts. Typical range: 0.01-0.10 (1%-10%)
                sigma:
                  type: number
                  default: 0.01
                  description: >-
                    Volatility of the short rate (annualized). Controls the
                    randomness of rate movements. Typical range: 0.005-0.02
                r0:
                  type: number
                  default: 0.03
                  description: >-
                    Initial short rate (annualized). Current spot rate. Typical
                    range: 0.00-0.10 (0%-10%)
                maturities:
                  type: array
                  items:
                    type: number
                  description: >-
                    Array of bond maturities in years (e.g., [0.25, 0.5, 1, 2,
                    5, 10] for 3M, 6M, 1Y, 2Y, 5Y, 10Y bonds)
              example:
                model: vasicek
                kappa: 0.15
                theta: 0.05
                sigma: 0.012
                r0: 0.03
                maturities:
                  - 0.25
                  - 0.5
                  - 1
                  - 2
                  - 5
                  - 10
      responses:
        '200':
          description: Successfully calculated bond prices
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      model:
                        type: string
                        example: vasicek
                      bonds:
                        type: array
                        items:
                          type: object
                          properties:
                            maturity:
                              type: number
                              description: Bond maturity in years
                            bond_price:
                              type: number
                              description: Zero-coupon bond price (per $100 face value)
                    example:
                      model: vasicek
                      bonds:
                        - maturity: 0.25
                          bond_price: 99.25
                        - maturity: 0.5
                          bond_price: 98.51
                        - maturity: 1
                          bond_price: 97.05
                        - maturity: 2
                          bond_price: 94.18
                        - maturity: 5
                          bond_price: 86.07
                        - maturity: 10
                          bond_price: 74.08
        '401':
          $ref: '#/components/responses/UnauthorizedError'
        '402':
          $ref: '#/components/responses/InsufficientCreditsError'
        '422':
          $ref: '#/components/responses/ValidationError'
components:
  responses:
    UnauthorizedError:
      description: Authentication information is missing or invalid
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Invalid API key
    InsufficientCreditsError:
      description: Insufficient credits to complete the request
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: >-
                  Insufficient credits. This endpoint requires 5 credits.
                  Current balance: 2 credits.
    ValidationError:
      description: Request validation failed
      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
                  - kappa
                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

````