Hi @sidharth_kothar 
To add giftcard with cart, please use following API:
URL : /V1/carts/{cartId}/giftCards
Method : PUT
Token: Customer Token
Request:
{
  "giftCardAccountData": {
    "gift_cards": [
      "string"
    ],
    "gift_cards_amount": 0,
    "base_gift_cards_amount": 0,
    "gift_cards_amount_used": 0,
    "base_gift_cards_amount_used": 0,
    "extension_attributes": {}
  }
}This is the only way to apply giftcard coupon with cart for customer.
For adding a product to cart with custom options like receipent email or message, you need to call below url:
url : /V1/carts/mine/items
Method: post
Token: Customer
Request :
{
    "cart_item": {
        "quote_id": "9",
        "sku": "24-MB01",
        "qty": 1,
        "productOption":{
            "extensionAttributes":{
                "customOptions":[
                    {
                        "optionId":"1",
                        "optionValue":"2"
                    }
                    ]
            }
        }
    }
}
If issue resolve, Please click on 'Kudos' & Accept as Solution!
 
					
				
			
			
				
	Problem solved? Click Accept as Solution!