# Variables de Entorno { #environment-variables }

/// tip | Consejo

Si ya sabes qué son las "variables de entorno" y cómo usarlas, siéntete libre de saltarte esto.

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Una variable de entorno (también conocida como "**env var**") es una variable que vive **fuera** del código de Python, en el **sistema operativo**, y podría ser leída por tu código de Python (o por otros programas también).

# Variáveis de Ambiente { #environment-variables }

/// tip | Dica

Se você já sabe o que são "variáveis de ambiente" e como usá-las, pode pular esta seção.

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Uma variável de ambiente (também conhecida como "**env var**") é uma variável que existe **fora** do código Python, no **sistema operacional**, e pode ser lida pelo seu código Python (ou por outros programas também).

When you work in Python projects you probably should use a **virtual environment** (or a similar mechanism) to isolate the packages you install for each project.

/// info

If you already know about virtual environments, how to create them and use them, you might want to skip this section. 🤓

///

/// tip

A **virtual environment** is different than an **environment variable**.

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Эта команда создаст или изменит некоторые [переменные окружения](environment-variables.md){.internal-link target=_blank}, которые будут доступны для следующих команд.

Одна из таких переменных — `PATH`.

/// tip | Подсказка

Вы можете узнать больше о переменной окружения `PATH` в разделе [Переменные окружения](environment-variables.md#path-environment-variable){.internal-link target=_blank}.

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Dieser Befehl erstellt oder ändert einige [Umgebungsvariablen](environment-variables.md){.internal-link target=_blank}, die für die nächsten Befehle verfügbar sein werden.

Eine dieser Variablen ist die `PATH`-Variable.

/// tip | Tipp

Sie können mehr über die `PATH`-Umgebungsvariable im Abschnitt [Umgebungsvariablen](environment-variables.md#path-environment-variable){.internal-link target=_blank} erfahren.

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Esse comando criará ou modificará algumas [variáveis ​​de ambiente](environment-variables.md){.internal-link target=_blank} que estarão disponíveis para os próximos comandos.

Uma dessas variáveis ​​é a variável `PATH`.

/// tip | Dica

Você pode aprender mais sobre a variável de ambiente `PATH` na seção [Variáveis ​​de ambiente](environment-variables.md#path-environment-variable){.internal-link target=_blank}.

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Ese comando creará o modificará algunas [variables de entorno](environment-variables.md){.internal-link target=_blank} que estarán disponibles para los siguientes comandos.

Una de esas variables es la variable `PATH`.

/// tip | Consejo

Puedes aprender más sobre la variable de entorno `PATH` en la sección [Variables de Entorno](environment-variables.md#path-environment-variable){.internal-link target=_blank}.

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To understand environment variables you can read [Environment Variables](../environment-variables.md){.internal-link target=_blank}.

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## Types and validation { #types-and-validation }

These environment variables can only handle text strings, as they are external to Python and have to be compatible with other programs and the rest of the system (and even with different operating systems, as Linux, Windows, macOS).

# Conditional OpenAPI { #conditional-openapi }

If you needed to, you could use settings and environment variables to configure OpenAPI conditionally depending on the environment, and even disable it entirely.

## About security, APIs, and docs { #about-security-apis-and-docs }

Hiding your documentation user interfaces in production *shouldn't* be the way to protect your API.

from fastapi import FastAPI, Request

app = FastAPI(
    servers=[
        {"url": "https://stag.example.com", "description": "Staging environment"},
        {"url": "https://prod.example.com", "description": "Production environment"},
    ],
    root_path="/api/v1",
)


@app.get("/app")
def read_main(request: Request):