Reading schemas

In this site’s JSON Schema examples, the styling of a property tells you what it means in the schema’s dialect.

JSON Schema · 2020-12

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://example.com/person",
  "$comment": "A person, with their address",
  "type": "object",
  "properties": {
    "name": { "type": "string" },
    "nickname": { "type": "string", "maxLenght": 20 },
    "address": { "$ref": "#/$defs/address" }
  },
  "$defs": {
    "address": { "$anchor": "address", "type": "string" }
  }
}

In draft-04 through draft-07, a $ref replaces the schema it’s in. The whole object is the reference and the rest of it has no effect.

JSON Schema · draft-07

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "definitions": { "name": { "type": "string" } },
  "properties": {
    "name": { "$ref": "#/definitions/name", "minLength": 1 }
  }
}

In v1, a property that starts with x- is an annotation, not an unknown keyword.

JSON Schema · v1

{
  "$schema": "https://json-schema.org/v1",
  "type": "string",
  "x-deprecated": true
}

Looks like	Means	In the examples
Bold name	A keyword	type, properties
Bold italic name	A core keyword: one that identifies, references, or holds schemas	$schema, $id, $ref, $defs
Bold value	The dialect, from $schema	https://json-schema.org/draft/2020-12/schema
Dotted underline	An identifier	The values of $id and $anchor
Underline	A reference	#/$defs/address, and all of the draft-07 object with $ref
Gray italic	Has no effect, like a comment	$comment, the misspelled maxLenght, and minLength next to the draft-07 $ref
Italic name	An annotation in v1	x-deprecated
Plain name	Not a keyword	name, nickname, address

On a lint rule’s page, what the rule reports also has a wavy underline. It’s orange for a warning and red for an error. The message follows the example.

Each example’s header says what it is: either JSON Schema and its dialect, or JSON that isn’t a schema.