Pydantic Settings

import os

# If you set PORT=8000 in your environment:
port = os.getenv("PORT")
print(type(port))  # <class 'str'> - not an integer!

# If you set DEBUG=False in your environment:
debug = os.getenv("DEBUG")
print(type(debug))  # <class 'str'>
if debug:
    # This runs! Because "False" is a non-empty string, which evaluates to True.
    print("Debug mode active")

pip install pydantic-settings

uv add pydantic-settings

from pydantic_settings import BaseSettings

class Settings(BaseSettings):
    api_key: str
    port: int = 8000
    debug: bool = False

# Instantiation
settings = Settings()

API_KEY=sk_test_123
PORT=5000
DEBUG=True

from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env")
    
    api_key: str
    port: int = 8000
    debug: bool = False

settings = Settings()
print(settings.api_key)  # sk_test_123
print(settings.port)     # 5000 (parsed as integer)

MYAPP_API_KEY=sk_test_123
MYAPP_PORT=5000

from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=".env",
        env_prefix="myapp_"
    )
    
    api_key: str
    port: int = 8000

settings = Settings()
# Now reads from MYAPP_API_KEY and MYAPP_PORT
print(settings.api_key)  # sk_test_123

from pydantic import SecretStr
from pydantic_settings import BaseSettings

class Settings(BaseSettings):
    database_password: SecretStr

settings = Settings(database_password="super-secret-password")

# Secrets are hidden when printed
print(settings.database_password)
# database_password=SecretStr('**********')

# Access the actual value when needed
print(settings.database_password.get_secret_value())
# super-secret-password

from functools import lru_cache
from pydantic_settings import BaseSettings

class Settings(BaseSettings):
    api_key: str

@lru_cache
def get_settings():
    return Settings()

# Use throughout your app
settings = get_settings()

from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env")
    
    environment: str = "development"
    debug: bool = False
    
    @property
    def is_production(self) -> bool:
        return self.environment == "production"

settings = Settings()
if settings.is_production:
    # Production-specific behavior
    pass