Highnote Transactions API

openapi: 3.0.1
info:
  title: Highnote GraphQL API
  description: >-
    The Highnote embedded-finance platform is driven by a single GraphQL endpoint.
    This OpenAPI document models the GraphQL-over-HTTP surface: a single
    POST /graphql operation that accepts a GraphQL query or mutation plus optional
    variables, authenticated with HTTP Basic auth using a base64-encoded API key
    as the username (no password). See graphql/highnote-graphql.md and
    graphql/highnote-schema.graphql for the GraphQL types, queries, and mutations.
  termsOfService: https://highnote.com/legal
  contact:
    name: Highnote
    url: https://docs.highnote.com
  version: '1.0'
servers:
  - url: https://api.us.highnote.com
    description: Live environment
  - url: https://api.us.test.highnote.com
    description: Test environment
security:
  - basicAuth: []
tags:
  - name: GraphQL
    description: Single GraphQL endpoint for all Highnote operations.
paths:
  /graphql:
    post:
      operationId: postGraphql
      tags:
        - GraphQL
      summary: Execute a GraphQL query or mutation
      description: >-
        Executes a GraphQL operation against the Highnote platform. The request body
        is a JSON object with a `query` string (which may contain a query or a
        mutation), an optional `variables` object, and an optional `operationName`.
        Responses always return HTTP 200 with a `data` and/or `errors` field per the
        GraphQL-over-HTTP convention.
      security:
        - basicAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/GraphQLRequest'
            examples:
              ping:
                summary: Health check query
                value:
                  query: 'query { ping }'
              listCardProducts:
                summary: List card products
                value:
                  query: >-
                    query { cardProducts(first: 10) { edges { node { id name type
                    status } } pageInfo { hasNextPage endCursor } } }
              issuePaymentCard:
                summary: Issue a virtual payment card
                value:
                  query: >-
                    mutation IssueCard($applicationId: ID!) {
                    issuePaymentCardForApplication(input: { applicationId:
                    $applicationId, formFactor: VIRTUAL }) { id bin last4
                    expirationDate network status } }
                  variables:
                    applicationId: card_product_application_id
      responses:
        '200':
          description: >-
            GraphQL response. Returns HTTP 200 even when the operation produces
            GraphQL errors; inspect the `errors` array.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GraphQLResponse'
        '401':
          description: Missing or invalid API key (Basic auth).
        '429':
          description: Rate limited. Retry with backoff.
components:
  securitySchemes:
    basicAuth:
      type: http
      scheme: basic
      description: >-
        HTTP Basic auth. The base64-encoded API key is supplied as the username and
        the password is left empty. Equivalent to sending
        `Authorization: Basic <base64(apiKey)>`.
  schemas:
    GraphQLRequest:
      type: object
      required:
        - query
      properties:
        query:
          type: string
          description: The GraphQL query or mutation document.
        variables:
          type: object
          additionalProperties: true
          description: Optional variable values referenced by the query document.
        operationName:
          type: string
          description: Optional operation name when the document defines multiple operations.
    GraphQLResponse:
      type: object
      properties:
        data:
          type: object
          additionalProperties: true
          nullable: true
          description: The result of the executed operation, keyed by field name.
        errors:
          type: array
          description: GraphQL errors, if any were produced during execution.
          items:
            $ref: '#/components/schemas/GraphQLError'
    GraphQLError:
      type: object
      properties:
        message:
          type: string
        path:
          type: array
          items:
            type: string
        extensions:
          type: object
          additionalProperties: true