An <a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">environment variable</a> (also known as "env var") is a variable that lives outside of the Python code, in the operating system, and could be read by your Python code (or by other programs as well).

You can create and use environment variables in the shell, without needing Python:

This doesn't go inside of each JSON Schema contained in OpenAPI, this goes outside, in the *path operation* directly.

### Using the `openapi_examples` Parameter

You can declare the OpenAPI-specific `examples` in FastAPI with the parameter `openapi_examples` for:

* `Path()`
* `Query()`

Nevertheless, you would probably also want to have something outside making sure to **restart Gunicorn** if necessary, and also to **run it on startup**, etc.

## Uvicorn with Workers

Uvicorn also has an option to start and run several **worker processes**.

    * Updated `examples` field in `Query()`, `Cookie()`, `Body()`, etc. based on the latest JSON Schema and OpenAPI. Now it takes a list of examples and they are included directly in the JSON Schema, not outside. Read more about it (including the historical technical details) in the updated docs: <a href="https://fastapi.tiangolo.com/tutorial/schema-extra-example/" class="external-link" target="_blank">Tutorial: Declare Request Example Data</a>.

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