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title: Pydantic Programs | LlamaIndex OSS Documentation
---

Tip

Pydantic Programs are a lower-level abstraction for structured output extraction. The default way to perform structured output extraction is with our LLM classes, which lets you plug these LLMs easily into higher-level workflows. Check out our [structured data extraction tutorial](/python/framework/understanding/extraction/index.md).

A pydantic program is a generic abstraction that takes in an input string and converts it to a structured Pydantic object type.

Because this abstraction is so generic, it encompasses a broad range of LLM workflows. The programs are composable and be for more generic or specific use cases.

There’s a few general types of Pydantic Programs:

- **Text Completion Pydantic Programs**: These convert input text into a user-specified structured object through a text completion API + output parsing.
- **Function Calling Pydantic Programs**: These convert input text into a user-specified structured object through an LLM function calling API.
- **Prepackaged Pydantic Programs**: These convert input text into prespecified structured objects.

## Text Completion Pydantic Programs

See the example notebook on [LLM Text Completion programs](/python/examples/output_parsing/llm_program/index.md)

## Function Calling Pydantic Programs

- [Function Calling Pydantic Program](/python/examples/output_parsing/function_program/index.md)
- [OpenAI Pydantic Program](/python/examples/output_parsing/openai_pydantic_program/index.md)
- [Guidance Pydantic Program](/python/examples/output_parsing/guidance_pydantic_program/index.md)
- [Guidance Sub-Question Generator](/python/examples/output_parsing/guidance_sub_question/index.md)

## Prepackaged Pydantic Programs

- [DF Program](/python/examples/output_parsing/df_program/index.md)
- [Evaporate Program](/python/examples/output_parsing/evaporate_program/index.md)