Glossary term

Structured output

Model output constrained to a defined format, such as valid JSON.

How it works

Structured output constrains a model to a defined format, typically JSON that matches a schema. Some systems enforce this while generating, by only allowing tokens that keep the output valid. That makes the result safe to parse in code.

Getting structured output

Step 1Define a schema
Step 2Model generates within it
Step 3Validate
Step 4Use in your program

In code

A JSON schema and a matching output

{
  "schema": {"type": "object", "properties": {"name": {"type": "string"}, "age": {"type": "integer"}}},
  "output": {"name": "Ana", "age": 31}
}

Why it matters

Software cannot depend on free-form text, so structured output is essential for connecting models to applications.

Related terms

Function calling Tool use Stop sequence