Validate JSON data with schemas, types, required fields, formats, composition, and API contracts.
Lessons
Allow, restrict, or forbid extra keys.
additionalProperties is easiest to learn by reading the example, changing it, and observing the result.
{
"type": "object",
"properties": {
"slug": { "type": "string" },
"title": { "type": "string" }
},
"additionalProperties": false
}Practice the additionalProperties example in a small scratch file, then explain what changed and why.