Generating structured data from unstructured inputs is one of the core use cases for AI in today’s applications. Developers use the OpenAI API to build powerful assistants that have the ability to fetch data and answer questions via function calling⁠(opens in a new window), extract structured data for data entry, and build multi-step agentic workflows that allow LLMs to take actions. Developers have long been working around the limitations of LLMs in this area via open source tooling, prompting, and retrying requests repeatedly to ensure that model outputs match the formats needed to interoperate with their systems. Structured Outputs solves this problem by constraining OpenAI models to match developer-supplied schemas and by training our models to better understand complicated schemas.

On our evals of complex JSON schema following, our new model gpt-4o-2024-08-06 with Structured Outputs scores a perfect 100%. In comparison, gpt-4-0613 scores less than 40%.

With Structured Outputs, gpt-4o-2024-08-06 achieves 100% reliability in our evals, perfectly matching the output schemas.

1. Function calling: Structured Outputs via tools is available by setting strict: true within your function definition. This feature works with all models that support tools, including all models gpt-4-0613 and gpt-3.5-turbo-0613 and later. When Structured Outputs are enabled, model outputs will match the supplied tool definition.