JSON Schema Validation - Validate JSON Structure

JSON Schema is a vocabulary for annotating and validating JSON documents. It lets you define the expected structure, types, and constraints for your data — then automatically check whether a JSON document conforms to those rules. It's widely used for API validation, configuration files, and data interchange formats.

A JSON Schema is itself a JSON object. The simplest schema specifies a type:

{ "type": "string" }	Value must be a string
{ "type": "number" }	Value must be a number
{ "type": "boolean" }	Value must be true or false
{ "type": "object" }	Value must be an object
{ "type": "array" }	Value must be an array
{ "type": "null" }	Value must be null

Objects are the most common type to validate. Key keywords:

properties	Define schemas for specific keys
required	Array of keys that must be present
additionalProperties	Whether extra keys are allowed (default: true)
minProperties / maxProperties	Limit the number of keys

Example: { "type": "object", "required": ["name"], "properties": { "name": { "type": "string" } } }

items	Schema that every element must match
minItems / maxItems	Limit the number of elements
uniqueItems	All elements must be distinct

Example: { "type": "array", "items": { "type": "string" }, "minItems": 1 } — a non-empty array of strings.

minLength / maxLength	String length limits
pattern	Regex pattern the string must match
format	Semantic format: date, email, uri, ipv4, etc.
minimum / maximum	Number range limits
enum	Value must be one of the listed options

Formats like date, email, and uri are fully validated — an invalid email address will be flagged as an error.

In the JSON Workbench, the schema validator appears as a collapsible card above the output area whenever you have valid JSON loaded:

• Load sample — Click to load a sample schema that demonstrates common validation rules.
• Paste your own — Expand the card and paste any JSON Schema into the textarea.
• Live validation — Errors update instantly as you edit either the JSON or the schema.
• Click errors — Click any error path to jump to that location in the tree viewer.
• Persistent — Your schema is saved to localStorage and restored on reload.