Validate Environment Variables with Pydantic

Tip! Validate your env vars from your .env files before they hit your application by using Pydantic. This also eliminates the need to call python-dotenv manually.

Here's an example:

# uv add pydantic pydantic-settings python-dotenv
from pydantic import Field, AnyHttpUrl, ValidationError
from pydantic_settings import BaseSettings, SettingsConfigDict

# Define settings schema
class Settings(BaseSettings):
    device_host: AnyHttpUrl = Field(..., alias="DEVICE_HOST")
    device_username: str = Field(..., alias="DEVICE_USERNAME")
    device_password: str = Field(..., alias="DEVICE_PASSWORD")
    device_platform: str = Field(..., alias="DEVICE_PLATFORM")

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        extra="ignore"
    )

try:
    settings = Settings()
    print(settings.device_username)
    # admin
except ValidationError as e:
    print(e)

# Validation Error example
# 1 validation error for Settings
# device_host
#   Input should be a valid URL, scheme required [type=url_scheme, input_value='192.168.1.10', input_type=str]
#     For further information visit https://errors.pydantic.dev/2.12/v/url_scheme