Input Schema

{
    "type": "object",
    "required": [
        "checkout_id"
    ],
    "properties": {
        "buyer": {
            "type": "object",
            "required": [],
            "properties": {
                "email": {
                    "type": "string",
                    "description": "Customer email address"
                },
                "full_name": {
                    "type": "string",
                    "description": "Customer full name"
                },
                "phone_number": {
                    "type": "string",
                    "description": "Customer phone number"
                }
            },
            "description": "Optional buyer information update"
        },
        "payment": {
            "type": "object",
            "required": [],
            "properties": {
                "instruments": {
                    "type": "array",
                    "items": {
                        "type": "object"
                    },
                    "description": "Array of payment instruments"
                },
                "selected_instrument_id": {
                    "type": "string",
                    "description": "ID of selected payment instrument"
                }
            },
            "description": "Optional payment update"
        },
        "discounts": {
            "type": "array",
            "items": {
                "type": "string"
            },
            "description": "Coupon or discount codes to apply to this session. Each element is a string code (e.g. \"DISCOUNT2026\"). Pass an empty array to remove all applied codes."
        },
        "line_items": {
            "type": "array",
            "items": {
                "type": "object",
                "required": [
                    "item",
                    "quantity"
                ],
                "properties": {
                    "id": {
                        "type": "string",
                        "description": "Line item ID (optional for new items)"
                    },
                    "item": {
                        "type": "object",
                        "required": [
                            "id"
                        ],
                        "properties": {
                            "id": {
                                "type": "string",
                                "description": "Product ID or variation ID"
                            }
                        },
                        "description": "Item reference with product or variation ID"
                    },
                    "quantity": {
                        "type": "integer",
                        "minimum": 0,
                        "description": "Quantity"
                    },
                    "parent_id": {
                        "type": "string",
                        "description": "Parent line item ID for variations"
                    }
                }
            },
            "description": "Complete replacement list of all line items for the session. Include ALL items you want in the cart (both existing and new) \u2014 this replaces the current line_items entirely, not appends to them."
        },
        "checkout_id": {
            "type": "string",
            "description": "Checkout session ID to update"
        },
        "fulfillment": {
            "type": "object",
            "required": [],
            "properties": {
                "methods": {
                    "type": "array",
                    "items": {
                        "type": "object",
                        "required": [],
                        "properties": {
                            "type": {
                                "enum": [
                                    "shipping",
                                    "pickup",
                                    "digital"
                                ],
                                "type": "string",
                                "description": "Fulfillment method type"
                            },
                            "groups": {
                                "type": "array",
                                "items": {
                                    "type": "object"
                                },
                                "description": "Fulfillment groups for this method"
                            },
                            "destinations": {
                                "type": "array",
                                "items": {
                                    "type": "object"
                                },
                                "description": "Available destinations for this method"
                            },
                            "line_item_ids": {
                                "type": "array",
                                "items": {
                                    "type": "string"
                                },
                                "description": "Line items for this fulfillment method"
                            },
                            "selected_destination_id": {
                                "type": "string",
                                "description": "Selected destination ID"
                            }
                        }
                    },
                    "description": "Array of fulfillment methods (shipping, pickup, digital)"
                }
            },
            "description": "Optional fulfillment update"
        }
    }
}