schema.json

{
    "$schema": "http://json-schema.org/draft-06/schema#",
    "title": "Product set",
    "type": "array",
    "items": {
        "title": "Product",
        "type": "object",
        "properties": {
            "name": {
                "description": "The name of the product (required)",
                "type": "string"
            },
            "ingredients": {
                "description": "The ingredients ordered by their relative weight, same as on the product packaging (required)",
                "type": "array",
                "items": {
                    "anyOf": [
                        { "type": "string"},
                        {
                            "type": "object",
                            "properties": {
                                "name":     {"type": "string"},
                                "resource": {"type": "string"}
                            },
                            "required": ["name", "resource"]
                        }
                    ]
                },
                "uniqueItems": true
            },
            "labels": {
                "description": "Labels on the product (required)",
                "type": ["array", "null"],
                "items": {
                    "type": "string"
                },
                "uniqueItems": true
            },
            "stores": {
                "description": "Store(s) selling the product (required)",
                "type": "array",
                "items": {
                    "type": "string"
                },
                "uniqueItems": true
            },
            "gtin": {
                "description": "The Global Trade Item Number or barcode (optional)",
                "type": "string"
            },
            "brand": {
                "description": "The brand of a product (optional)",
                "type": "string"
            },
            "producer": {
                "description": "The producing company (optional)",
                "type": "string"
            },
            "category": {
                "description": "The product category, ideally conforming to GS1 standards (optional)",
                "type": "string"
            },
            "details": {
                "description": "Any extra information (optional)",
                "type": "object",
                "properties": {
                    "size": {
                        "type": "object",
                        "properties": {
                            "amount": { "type": "number" },
                            "unit":   { "type": "string" }
                        }
                    },
                    "price": {
                        "type": "object",
                        "properties": {
                            "amount":   { "type": "number" },
                            "currency": { "type": "string" }
                        }
                    },
                    "image_url": { "type": "string" }
                },
                "additionalProperties": true
            }
        },
        "required": ["name", "ingredients", "labels", "stores"]
    }
}