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

# Convert CUSIPs to ISINs

> Convert a list of 9-character US CUSIPs into ISINs.

Inputs that do not match the 9-character CUSIP format are returned with `isin: null`.

Since all other endpoints require ISINs, this endpoint is useful to convert identifiers to ISINs before using other endpoints.


## OpenAPI

````yaml post /api/v1/convert_to_isin
openapi: 3.0.0
info:
  title: Terrapin API
  version: 1.0.0
servers:
  - url: https://terrapinfinance.com
    variables: {}
security:
  - authorization: []
tags: []
paths:
  /api/v1/convert_to_isin:
    post:
      tags: []
      summary: Convert CUSIPs to ISINs
      description: >
        Convert a list of 9-character US CUSIPs into ISINs.


        Inputs that do not match the 9-character CUSIP format are returned with
        `isin: null`.


        Since all other endpoints require ISINs, this endpoint is useful to
        convert identifiers to ISINs before using other endpoints.
      operationId: post_convert_to_isin
      parameters: []
      requestBody:
        content:
          application/json:
            example:
              identifiers:
                - '037833100'
                - '594918104'
            schema:
              additionalProperties: false
              properties:
                identifiers:
                  description: |
                    List of 9-character US CUSIPs to convert to ISINs.
                  items:
                    example: '037833100'
                    nullable: false
                    type: string
                    x-struct: null
                    x-validate: null
                  minItems: 1
                  type: array
                  x-check: valid_check_digit
                  x-check-error: Invalid ISIN check digit
                  x-struct: null
                  x-transform: upcase
                  x-validate: null
              required:
                - identifiers
              type: object
              x-struct: null
              x-validate: null
        required: true
      responses:
        '200':
          content:
            application/json:
              example:
                data:
                  - input: '037833100'
                    isin: US0378331005
                  - input: '594918104'
                    isin: US5949181045
                total: 2
              schema:
                additionalProperties: false
                properties:
                  data:
                    description: List of response data objects, often capped to 1000.
                    items:
                      additionalProperties: false
                      properties:
                        input:
                          description: >-
                            The original identifier that was provided in the
                            request.
                          example: '037833100'
                          nullable: false
                          type: string
                          x-struct: null
                          x-validate: null
                        isin:
                          description: >
                            The resolved ISIN for the given CUSIP, or `null` if
                            the input is not a valid 9-character CUSIP.
                          example: US0378331005
                          maxLength: 12
                          minLength: 12
                          nullable: true
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - input
                        - isin
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                  total:
                    description: >-
                      Total number of results in the database that match the
                      query filters.
                    type: integer
                    x-struct: null
                    x-validate: null
                required:
                  - data
                  - total
                title: ConvertToIsinResponse
                type: object
                x-struct: null
                x-validate: null
          description: Resolved ISINs per input identifier
        '401':
          content:
            application/json:
              schema:
                additionalProperties: false
                properties:
                  errors:
                    items:
                      additionalProperties: false
                      properties:
                        detail:
                          example: Unauthorized
                          type: string
                          x-struct: null
                          x-validate: null
                        reason:
                          example: >-
                            Your account tier does not allow this operation.
                            Contact team@terrapinfinance.com for an upgrade.
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Unauthorized
        '402':
          content:
            application/json:
              schema:
                additionalProperties: false
                properties:
                  errors:
                    items:
                      additionalProperties: false
                      properties:
                        detail:
                          example: Payment Required
                          type: string
                          x-struct: null
                          x-validate: null
                        reason:
                          example: >-
                            You have run out of your granted quota for this
                            resource as defined by your account tier. Contact
                            team@terrapinfinance.com for an upgrade.
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Payment Required
        '403':
          content:
            application/json:
              schema:
                additionalProperties: false
                properties:
                  errors:
                    items:
                      additionalProperties: false
                      properties:
                        detail:
                          example: Forbidden
                          type: string
                          x-struct: null
                          x-validate: null
                        reason:
                          example: >-
                            Your account tier does not allow this operation.
                            Contact team@terrapinfinance.com for an upgrade.
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Forbidden
        '422':
          content:
            application/json:
              schema:
                properties:
                  errors:
                    items:
                      properties:
                        detail:
                          example: 'Invalid string. Got: integer'
                          type: string
                          x-struct: null
                          x-validate: null
                        source:
                          properties:
                            pointer:
                              example: /isins/0
                              type: string
                              x-struct: null
                              x-validate: null
                          required:
                            - pointer
                          type: object
                          x-struct: null
                          x-validate: null
                        title:
                          example: Invalid value
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                        - source
                        - title
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Unprocessable Entity
        '429':
          content:
            application/json:
              schema:
                additionalProperties: false
                properties:
                  errors:
                    items:
                      additionalProperties: false
                      properties:
                        detail:
                          example: Too Many Requests
                          type: string
                          x-struct: null
                          x-validate: null
                        reason:
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Too Many Requests
        '500':
          content:
            application/json:
              schema:
                additionalProperties: false
                properties:
                  errors:
                    items:
                      additionalProperties: false
                      properties:
                        detail:
                          example: Internal Server Error
                          type: string
                          x-struct: null
                          x-validate: null
                        reason:
                          type: string
                          x-struct: null
                          x-validate: null
                      required:
                        - detail
                      type: object
                      x-struct: null
                      x-validate: null
                    type: array
                    x-struct: null
                    x-validate: null
                required:
                  - errors
                type: object
                x-struct: null
                x-validate: null
          description: Internal Server Error
      callbacks: {}
components:
  securitySchemes:
    authorization:
      scheme: bearer
      type: http

````