setting required on a json-schema array

I got it to work using this validator by nesting the part of the schema for the array elements inside a object with the name items. The schema now has two nested items fields, but that is because one is a keyword in JSONSchema and the other because your JSON actually has a field called items

JSONSchema:

{
   "type":"object",
   "properties":{
      "items":{
         "type":"array",
         "items":{
            "properties":{
               "item_id":{
                  "type":"number"
               },
               "quantity":{
                  "type":"number"
               },
               "price":{
                  "type":"number"
               },
               "title":{
                  "type":"string"
               },
               "description":{
                  "type":"string"
               }
            },
            "required":[
               "item_id",
               "quantity",
               "price",
               "title",
               "description"
            ],
            "additionalProperties":false
         }
      }
   }
}

JSON:

{
   "items":[
      {
         "item_id":1,
         "quantity":3,
         "price":30,
         "title":"item1 new name"
      },
      {
         "item_id":1,
         "quantity":16,
         "price":30,
         "title":"Test Two"
      }
   ]
}

Output with two errors about missing description fields:

[ {
  "level" : "error",
  "schema" : {
    "loadingURI" : "#",
    "pointer" : "/properties/items/items"
  },
  "instance" : {
    "pointer" : "/items/0"
  },
  "domain" : "validation",
  "keyword" : "required",
  "message" : "missing required property(ies)",
  "required" : [ "description", "item_id", "price", "quantity", "title" ],
  "missing" : [ "description" ]
}, {
  "level" : "error",
  "schema" : {
    "loadingURI" : "#",
    "pointer" : "/properties/items/items"
  },
  "instance" : {
    "pointer" : "/items/1"
  },
  "domain" : "validation",
  "keyword" : "required",
  "message" : "missing required property(ies)",
  "required" : [ "description", "item_id", "price", "quantity", "title" ],
  "missing" : [ "description" ]
} ]

Try pasting the above into here to see the same output generated.

Maybe your validator only supports JSONSchema v3?

The way required works changed between v3 and v4:

• In v3 required is a boolean: https://datatracker.ietf.org/doc/html/draft-zyp-json-schema-03#section-5.7
• In v4 required is an array of strings (like in your example): https://datatracker.ietf.org/doc/html/draft-fge-json-schema-validation-00#section-5.4.3

I realize this is an old thread, but since this question is linked from jsonschema.net, I thought it might be worth chiming in...

The problem with your original example is that you're declaring "properties" for an "array" type, rather than declaring "items" for the array, and then declaring an "object" type (with "properties") that populates the array. Here's a revised version of the original schema snippet:

"items": {
    "type": "array",
    "items": {
        "type": "object",
        "properties": {
            "item_id": {"type" : "number"},
            "quantity": {"type": "number"},
            "price": {"type" : "decimal"},
            "title": {"type": "string"},
            "description": {"type": "string"}
        },
        "required": ["item_id","quantity","price","title","description"],
        "additionalProperties" : false
    }
}

I would recommend against using the term "items" for the name of the array, to avoid confusion, but there's nothing stopping you from doing that...