# Get product swap variant groups for a contract

Retrieves product swap variant groups for the next 10 billing cycles of a specific subscription contract. This endpoint calculates and returns which products will be swapped to in future billing cycles based on configured swap automations.

Response Structure:
Returns a 2D array (List>):
- Outer array: Represents the next 10 billing cycles
- Inner arrays: Contains the variant(s) that will be swapped to for that specific cycle
- Index 0: Variants for the next (upcoming) billing cycle
- Index 1: Variants for the cycle after that
- And so on for the next 10 cycles

Variant Details:
Each variant object includes:
- variantId: Shopify variant ID
- quantity: Number of units to swap
- title: Variant title (e.g., "Medium Roast - 12oz")
- image: Product/variant image URL
- productTitle: Full product name
- productId: Shopify product GID
- variantTitle: Full display name combining product and variant titles
- swapId: ID of the swap automation rule that triggered this swap

How It Works:
1. Takes the current products in the subscription
2. Applies configured swap automations for the next 10 cycles
3. Calculates which products will be swapped based on:
   - Billing cycle number
   - Swap rule configurations (forBillingCycle, checkForEveryRecurringOrder)
   - Rule sequence/priority
4. Returns the projected product lineup for each cycle

Use Cases:
- Preview upcoming product swaps in customer portals
- Show customers their subscription product timeline
- Build interactive swap calendars
- Display "what you'll receive" for future orders
- Debug and verify swap automation configurations

Important Notes:
- Returns 10 cycles even if no swaps are configured (returns current products)
- Multiple variants in an inner array means multiple products will be in that order
- Empty inner arrays indicate no products for that cycle (rare edge case)
- The swapId can be used to trace which automation rule triggered the swap

Authentication: Requires valid X-API-Key header

Endpoint: POST /api/external/v2/product-swaps-by-variant-groups/{contractId}
Version: 0.0.1

## Query parameters:

  - `api_key` (string)
    API Key (Deprecated - Use Header X-API-Key instead)

## Header parameters:

  - `X-API-Key` (string)

## Path parameters:

  - `contractId` (integer, required)

## Request fields (application/json):

  - `variantQuantityList` (array)

  - `variantQuantityList.variantId` (integer)

  - `variantQuantityList.quantity` (integer)

  - `variantQuantityList.title` (string)

  - `variantQuantityList.image` (string)

  - `variantQuantityList.productTitle` (string)

  - `variantQuantityList.productId` (string)

  - `variantQuantityList.variantTitle` (string)

  - `variantQuantityList.swapId` (integer)


## Response 200 fields

## Response 400 fields

## Response 401 fields

## Response 403 fields

## Response 404 fields