# Get all one-time products for a subscription contract

Retrieves all one-time products (add-ons) associated with a specific subscription contract across all billing attempts. One-time products are additional items that customers can add to their subscription orders on a non-recurring basis. Each one-time product is tied to a specific billing attempt and will only be included in that particular order.

Key Features:
- Returns ALL one-time products across all queued billing attempts
- Each product includes the billing attempt ID to identify which order it belongs to
- Includes product details: variant ID, quantity, title, image, and price
- Products are automatically removed after the associated billing attempt is processed

Use Cases:
- Display all one-time products added to a subscription across all upcoming orders
- Allow customers to review their one-time add-ons in customer portal
- Enable merchants to see all one-time products for a contract
- Integrate with external systems to manage subscription add-ons

Authentication: Requires valid X-API-Key header

Endpoint: GET /api/external/v2/subscription-contract-one-offs-by-contractId
Version: 0.0.1

## Header parameters:

  - `X-API-Key` (string, required)
    API Key for authentication. This key identifies your shop and must be included in the X-API-Key header.
    Example: "sk_live_1234567890abcdef"

## Query parameters:

  - `contractId` (integer, required)
    The unique identifier of the subscription contract to retrieve one-time products for
    Example: 98765

  - `api_key` (string)
    API Key (Deprecated - Use X-API-Key header instead)
    Example: "sk_live_1234567890abcdef"

## Response 200 fields (application/json):

  - `id` (integer)
    Unique identifier of the one-time product record
    Example: 12345

  - `shop` (string, required)
    The Shopify store domain that owns this subscription
    Example: "example-store.myshopify.com"

  - `billingAttemptId` (integer)
    The billing attempt ID this one-time product is associated with. This determines which upcoming order will include this product.
    Example: 54321

  - `subscriptionContractId` (integer)
    The subscription contract ID this one-time product belongs to
    Example: 98765

  - `variantId` (integer)
    The Shopify product variant ID for this one-time product
    Example: 42549172011164

  - `variantHandle` (string)
    The handle/slug of the product variant for URL-friendly identification
    Example: "premium-coffee-blend-500g"

  - `quantity` (integer)
    The quantity of this product to include in the order
    Example: 2

  - `price` (number)
    The price per unit of this product in the shop's base currency. This may include any applicable discounts.
    Example: 19.99


## Response 400 fields

## Response 401 fields

## Response 403 fields