Stream structured data, not just text

Streaming text is easy. Streaming typed data—where you can access fields as they arrive—that's the BAML difference.

Access partial.title before the full response is done. Build real-time UIs that show fields as they're ready.

main.baml
class Article {
  title string
  summary string @description("2-3 sentence summary")
  keyPoints string[] @description("3-5 bullet points")
  sentiment Sentiment
}

enum Sentiment {
  POSITIVE
  NEGATIVE
  NEUTRAL
}

function SummarizeArticle(url: string) -> Article {
  client "openai/gpt-4o-mini"
  prompt #"
    Summarize the article at: {{ url }}
    {{ ctx.output_format }}
  "#
}
Click Run to see the rendered prompt
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