ListingItem

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://opensea.io/schemas/ListingItem",
  "title": "ListingItem",
  "type": "object",
  "description": "An item to list for sale",
  "properties": {
    "chain": {
      "type": "string",
      "description": "Chain of the item (e.g. 'ethereum', 'base')",
      "example": "ethereum"
    },
    "contract": {
      "type": "string",
      "description": "Contract address of the NFT",
      "example": "0x..."
    },
    "token_id": {
      "type": "string",
      "description": "Token ID of the NFT",
      "example": 1234
    },
    "quantity": {
      "type": "integer",
      "format": "int64",
      "description": "Quantity to list (use 1 for ERC-721)",
      "example": 1
    },
    "price": {
      "$ref": "#/components/schemas/ListingPrice",
      "description": "Price per item"
    },
    "start_time": {
      "type": "string",
      "description": "Listing start time in ISO 8601 format. Defaults to now.",
      "example": "2026-05-01T00:00:00Z"
    },
    "end_time": {
      "type": "string",
      "description": "Listing end time in ISO 8601 format. Defaults to 30 days from start.",
      "example": "2026-06-01T00:00:00Z"
    }
  },
  "required": [
    "chain",
    "contract",
    "price",
    "quantity",
    "token_id"
  ]
}