If you have an old FastAPI app, you might be using Pydantic version 1.

FastAPI version 0.100.0 had support for either Pydantic v1 or v2. It would use whichever you had installed.

FastAPI version 0.119.0 introduced partial support for Pydantic v1 from inside of Pydantic v2 (as `pydantic.v1`), to facilitate the migration to v2.

FastAPI 0.126.0 dropped support for Pydantic v1, while still supporting `pydantic.v1` for a little while.

/// warning

as in:

{* ../../docs_src/body_nested_models/tutorial008_py39.py hl[13] *}

## Editor support everywhere { #editor-support-everywhere }

And you get editor support everywhere.

Even for items inside of lists:

<img src="/img/tutorial/body-nested-models/image01.png">

You couldn't get this kind of editor support if you were working directly with `dict` instead of Pydantic models.

#     v2: Build TF v2
#
# Feature and Third party library support options:
#     xla:          Build TF with XLA
#     tpu:          Build TF with TPU support
#     cuda:         Build with CUDA support.
#     cuda_clang    Build with CUDA Clang support.
#     rocm:         Build with AMD GPU support (rocm)
#     mkl:          Enable full mkl support.
#     nogcp:        Disable GCS support.
#     nonccl:       Disable nccl support.
#
#

<img src="/img/tutorial/body/image01.png">

And will also be used in the API docs inside each *path operation* that needs them:

<img src="/img/tutorial/body/image02.png">

## Editor support { #editor-support }

In your editor, inside your function you will get type hints and completion everywhere (this wouldn't happen if you received a `dict` instead of a Pydantic model):

<img src="/img/tutorial/body/image03.png">

Nevertheless, at the <abbr title="2023-08-26">time of writing this</abbr>, Swagger UI, the tool in charge of showing the docs UI, doesn't support showing multiple examples for the data in **JSON Schema**. But read below for a workaround.

### OpenAPI-specific `examples` { #openapi-specific-examples }

Since before **JSON Schema** supported `examples` OpenAPI had support for a different field also called `examples`.

The AGPLv3 provides no obligation by any party to support, maintain, or warranty the original or any modified work.
All support is provided on a best-effort basis through Github and our [Slack](https//slack.min.io) channel, and any member of the community is welcome to contribute and assist others in their usage of the software.

**Key Test Areas**:
- Improved error messages with encoding
- Various encoding support
- Edge cases (empty, large, Unicode)
- Special characters handling

**Test Count**: 12 tests

**Key Scenarios**:
- ✅ Default UTF-8 encoding extraction
- ✅ Custom encoding support
- ✅ Error messages include encoding information
- ✅ Large content handling
- ✅ Unicode and special characters

## Version 5.2.0

_2025-10-07_

 *  New: Support [HTTP 101] responses with `Response.socket`. This mechanism is only supported on
    HTTP/1.1. We also reimplemented our websocket client to use this new mechanism.

 *  New: The `okhttp-zstd` module negotiates [Zstandard (zstd)][zstd] compression with servers that
    support it. It integrates a new (unstable) [ZSTD-KMP] library, also from Square. Enable it like

* Edit the text of the PR title to start in "imperative", like giving an order. So, instead of `Adding support for teleporting` use `Add support for teleporting`.

# Python Types Intro { #python-types-intro }

Python has support for optional "type hints" (also called "type annotations").

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.