Validate JSON data with schemas, types, required fields, formats, composition, and API contracts.
Lessons
Keep core keywords and patterns at your fingertips.
JSON Schema Cheatsheet is easiest to learn by reading the example, changing it, and observing the result.
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "https://example.com/schemas/lesson.json",
"title": "Lesson",
"type": "object",
"required": ["slug", "title"],
"properties": {
"slug": { "type": "string", "pattern": "^[a-z0-9-]+$" },
"title": { "type": "string", "minLength": 3, "maxLength": 80 },
"minutes": { "type": "integer", "minimum": 1 },
"level": { "type": "string", "enum": ["beginner", "advanced"] },
"tags": { "type": "array", "items": { "type": "string" }, "uniqueItems": true }
},
"additionalProperties": false
}Practice the JSON Schema Cheatsheet example in a small scratch file, then explain what changed and why.