Structured Output

What it means

Asking an AI model to return information in a predefined format, such as JSON.

Code example

const res = await openai.chat.completions.create({
  model: "gpt-4o",
  response_format: { type: "json_object" },
  messages: [{ role: "user", content: "Return {name, age} for Alice, 30" }],
});
console.log(JSON.parse(res.choices[0].message.content));

Why it matters

It makes responses easier to consume programmatically and integrate into frontends, APIs and databases.

When to use it

• Extracting JSON from text
• Filling forms
• Generating config files