[Fixed] Pydantic V2 error using FastAPI + SQLModel – Fastapi

by
Alexei Petrov
fastapi postgresql pydantic python sqlmodel

Quick Fix: Downgrade pydantic to a version less than 2 using pip install "pydantic<2". This will ensure compatibility with SQLModel and resolve the error.

The Problem:

I’m encountering an error when using Pydantic V2 with FastAPI and SQLModel. I’ve been encountering PydanticImportError, specifically with the import pydantic.errors.ConfigError. Can you help pinpoint the issue and suggest a solution? My goal is to resolve this error and ensure compatibility with the latest Pydantic version.

The Solutions:

Solution 1: Downgrade Pydantic Version

The issue here is that SQLModel is not compatible with Pydantic V2. To resolve this problem, you can downgrade your Pydantic version by running the following command:

pip install "pydantic<2"

This will install the latest version of Pydantic that is compatible with SQLModel.

Q&A

Why am I getting a PydanticImportError?

SQLModel is not compatible with Pydantic V2. Downgrade Pydantic to version 1

Will downgrading Pydantic fix the issue?

Yes, it should resolve the issue

Is my FastAPI version compatible with Pydantic V1?

Yes, it is.

Video Explanation:

The following video, titled "FastAPI Tutorial - Building RESTful APIs with Python - YouTube", provides additional insights and in-depth exploration related to the topics discussed in this post.

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In this Python tutorial you will learn about FastAPI, a Web framework for developing RESTful APIs in Python.