Grain Pricing API

openapi: 3.2.0
info:
  title: Grain Pricing API
  version: 1.0.0
  description: Grain's API provides a comprehensive set of endpoints for managing hedging, currency conversions, pricing, and fund movements - enabling seamless integration of FX workflows into your platform. Each API call follows REST conventions, uses secure authentication, and returns standardized responses for consistency across environments.
  license:
    name: Creative Commons Attribution 3.0
  contact:
    name: Grain Finance
    url: https://docs.grainfinance.co
    email: support@grainfinance.co
  termsOfService: https://grainfinance.co/terms-of-service/
  x-apiClientRegistration:
    url: https://grainfinance.co/partners
servers:
- url: https://api.grainfinance.co/v1
  description: Grain API
tags:
- name: Pricing
  description: Pricing endpoints provide access to FX rates for currency pairs that are not being hedged. These endpoints can be used for live rate display or bulk retrieval to support high-volume quoting workflows.
paths:
  /rates/currency-pairs-exchange-rate:
    get:
      operationId: Rate
      responses:
        '200':
          description: Currency Pairs Exchange Rate
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SpotRatesResponseBody'
        '400':
          description: The request failed because it is not well-formed or is syntactically incorrect or violates schema.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AcceptOfflineHedgeBadParamsErrorResponse'
        '422':
          description: The request failed because it is either semantically incorrect or has failed business validation.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '500':
          description: The request failed because an internal server error occurred.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      description: Retrieves the current FX spot rate for supported currency pairs. Use this endpoint for real-time reference rates or live rate display.
      tags:
      - Pricing
      security:
      - api-key: []
      parameters:
      - description: (Optional) A query parameter specifying a comma-separated list of 3-letter ISO currency codes.
        in: query
        name: currencies
        required: false
        schema:
          type: string
      summary: Rate
      x-summary-source: derived
components:
  schemas:
    SpotRates:
      properties: {}
      type: object
      additionalProperties:
        properties: {}
        additionalProperties:
          type: number
          format: double
        type: object
    AcceptOfflineHedgeBadParamsErrorResponse:
      description: An API Error
      properties:
        message:
          type: string
          description: A short code of the error.
          example: REVISION_INVALID
        reason:
          type: string
          description: A detailed description of the reason for the failure.
          example: The revision number is not valid or does not exist. Please fetch a new rate table using the /offline-rates endpoint and pass a valid revision.
      required:
      - message
      type: object
      additionalProperties: false
    ErrorResponse:
      description: An API Error
      properties:
        message:
          type: string
          description: A short explanation of the error.
          example: Can't perform this action
        reason:
          type: string
          description: A detailed description of the reason for the failure.
          example: Supplied object is in *Cancelled* state, which prevents performing this action
      required:
      - message
      type: object
      additionalProperties: false
    SpotRatesResponseBody:
      properties:
        rates:
          $ref: '#/components/schemas/SpotRates'
      type: object
      additionalProperties: false
  securitySchemes:
    api-key:
      type: http
      scheme: basic
      description: Basic authentication using the partner API keys from https://console.grainfinance.co/keys