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

# Checkout Onramp Session

> Checkout a headless Stripe embedded onramp session and return the checkout client secret required by the Stripe embedded component. The session is resolved to the stored Link OAuth token server-side.



## OpenAPI

````yaml https://api.coinvoyage.io/v3/openapi.json post /onramp/sessions/{session_id}/checkout
openapi: 3.1.0
info:
  title: CoinVoyage API (v3)
  description: >-
    CoinVoyage v3 payment API. Unified Intent envelope, snake_case money via the
    Amount shape, and a single SHA-256 signature scheme.
  version: 3.0.0
servers:
  - url: https://api.coinvoyage.io/v3
security: []
paths:
  /onramp/sessions/{session_id}/checkout:
    post:
      tags:
        - onramp
      summary: Checkout Onramp Session
      description: >-
        Checkout a headless Stripe embedded onramp session and return the
        checkout client secret required by the Stripe embedded component. The
        session is resolved to the stored Link OAuth token server-side.
      operationId: checkoutOnrampSession
      parameters:
        - description: API key for authentication
          in: header
          name: X-API-KEY
          required: true
          schema:
            type: string
        - in: path
          name: session_id
          required: true
          schema:
            type: string
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OnrampCheckoutResponse'
          description: onramp checkout client secret created
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: onramp session ID is required
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Unauthorized
        '404':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: onramp session not found
        '500':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Failed to checkout onramp session
      security:
        - APIKeyHeader: []
components:
  schemas:
    OnrampCheckoutResponse:
      properties:
        client_secret:
          type: string
      required:
        - client_secret
      type: object
    ErrorResponse:
      example:
        code: 400
        error: Bad Request
        message: Invalid request parameters
      properties:
        error:
          example: Bad Request
          type: string
        message:
          example: Invalid request parameters
          type: string
        code:
          example: 400
          format: int64
          type: integer
        details:
          anyOf:
            - type: string
            - type: number
            - type: object
      required:
        - error
        - message
        - code
      type: object
  securitySchemes:
    APIKeyHeader:
      in: header
      name: X-API-KEY
      type: apiKey

````