Pydantic, Everywhere, All at Once - Unifying Data Models Across LLM Generation, FastAPI, and SQLModel

Explore the ambitious goal of creating unified Pydantic models that work seamlessly across constrained LLM generation, FastAPI inputs/outputs, and SQLModel ORM definitions in this 29-minute conference talk from EuroPython 2025. Discover whether maintaining "one data model to rule them all" is a practical solution or a recipe for complexity as you examine real-world scenarios where developers attempt to use a single source of truth for multiple purposes. Learn about the challenges and trade-offs involved in juggling Pydantic v1 versus v2 while managing constraints, endpoints, and SQL tables within the same model structure. Gain practical insights through concrete examples that demonstrate both the benefits and pitfalls of unified model approaches. Walk away with a clear decision-making framework for structuring your Pydantic models effectively and a strategic roadmap for maintaining sanity when implementing Pydantic across diverse use cases in your applications.