AI Structured Output Validator
Validate AI JSON output against a JSON Schema — check types, required fields, enums.
Related Tools
Visually build JSON schemas for AI function calling and structured output.
Fix broken LLM JSON: strip markdown fences, trailing commas, single quotes, and more.
Extract and fix JSON from mixed LLM output — handles prose, markdown, and concatenation.
Generate a structured output prompt from a JSON example or schema.
Parse and pretty-print SSE stream chunks from OpenAI and similar APIs.
Learn More
FAQ
- What does the validator check?
- The validator checks three things: (1) Required fields — all fields listed in the schema "required" array must be present in the output. (2) Type matching — each field value must match the declared type (string, number, boolean, array, object, null). (3) Enum values — if a field has an "enum" constraint, the value must be one of the allowed options.
- What does a JSON path error look like?
- Each error shows the dot-notation path to the problem (e.g., "user.address.zip"), the expected type or constraint, and the actual value or type found. This lets you immediately locate the offending field without manually comparing the documents.
- Can I use this to test function calling responses?
- Yes. Paste the function/tool schema definition in the left panel and the model's response JSON in the right panel. The validator checks that the response conforms to the schema you defined for the function.
Two-panel validator: paste a JSON Schema on the left and the AI-generated JSON output on the right. The validator checks that required fields are present, that value types match the schema, and that enum constraints are satisfied. Errors are listed with JSON path, expected type, and actual type — making it easy to pinpoint exactly what the model got wrong.