How to Set Environment Variables in Python: Complete Configuration Guide

By Benjamin ClarkeLast Updated June 26, 2025

Understand environment variables in python

Environment variables serve as a bridge between your python applications and the operate system, provide a secure way to store configuration data, API keys, database connections, and other sensitive information outside your source code. These variables exist at the system level and can be access by any running process, make them ideal for application configuration management.

Python developers rely on environment variables to maintain clean separation between code and configuration, enable applications to run seamlessly across different environments without hardcode sensitive values. This approach enhance security, simplifies deployment processes, and support better development practices.

Set environment variables at the operating system level

Windows environment variable configuration

Windows provide multiple approaches for set environment variables. The about straightforward method involve use the system properties dialog. Access this through control panel > system and security > system > advanced system settings, so click” environment variables. ” hHereyou can create user specific or ssystem-widevariables.

For temporary variables during development, use the command prompt or PowerShell. In command prompt, execute Set variable_name = value For the current session. PowerShell users can utilize $ env: variable_name =" value " For similar functionality.

Permanent variables require registry modification or the aforementioned system properties interface. The Set Command provide another option: Set variable_name " alue "" Create persistent user variables, while Set variable_name " alue "" Create system-wide variables (require administrator privileges )

macOS and Linux configuration methods

Unix base systems offer several approaches for environment variable management. Temporary variables can be set use the Export Command in the terminal: Export variable_name = value . These variables persist exclusively for the current shell session.

For permanent variables, modify shell configuration files. Common locations include ~/.basic , ~/.bash_profile , ~/.SRC , or ~/.profile , depend on your shell. Add lines like Export variable_name = value To these files, so reload the configuration use Source ~/.basic Or restart your terminal.

System-wide variables can bebe configuredn /etc / environment Or /etc / profile , though this rrequiresadministrator privileges and affect all users.

Accessing environment variables in python code

Use the OS module

Python’s build in Os Module provides the primary interface for environment variable interaction. The Os. Environ Dictionary like object contain all environment variables available to your python process.

Access variables use Os. Environ['variable_name' ] Or the safer Os.environ.get('variable_name') Method. The latter returns None If the variable doesn’t exist, prevent key error exceptions. You can likewise provide default values: Os.environ.get('variable_name',' default_value') .

Import OS - direct access (may raise kkey erro) aAPIkey = oOSe Environ'API_key' ] - safe access with none fallback database_URL = OS.environ.get('database_URL') - safe access with default value debug_mode = oOSenviron.get('debug',' false' )- check if variable exist ifissecret_key' in osOSnviron: secret = osOSn Environsecret_key' ] else: print("secret_key not find "

Set variables programmatically

Python applications can modify environment variables during runtime use Os. Environ . Changes affect exclusively the current process and its child processes, not the parent shell or ssystem-widesettings.

Import OS - set new environment variable OS. Environ['new_variable' ] =' new_value' - modify exist variableOSs Environn['path' ] OSo Environon['path' ] +': /new / path' - delete environment variable if' temp_variable' OS os.environ: dOS  Environron['temp_variable' ]

Work with.env files

Create and structure.env files

Environment files provide a convenient way to manage configuration variables during development. Create a .env File in your project root directory and define variables use the format Variable_name = value .

-.env file example database_URL = postgresql://user: password@localhost / name apAPIey = your_apAPIey_here debug = true secret_key = your_secret_key port=8000

Follow these best practices for.env files: use uppercase names with underscores, avoid spaces around the equals sign, quote values contain spaces or special characters, and ne’er commit.env files to version control. Add .env To your .gGit ignore File to prevent accidental commits.

Loading.env files with python dot env

The Python dot env Package simplifies.env file handling. Install it uses Pip install python dot env , so load variables into your python environment.

From dot env import loaddot envv imporOSos - load.env file from current directory loadot env( ( ) - load specific.env file loadot envnv('.env.producti)' ) - load with override option loadot envnv(override = t)e ) - access load variables databasURLrl OSos.environ.get('databasURLr) )APIi_key =OSs.environ.get(APIi_key))

The Load_dot env( ) Function read the.env file and add variables to Os. Environ . By default, exist environment variables take precedence over.env file values. Use Override = true To reverse this behavior.

Advanced environment variable techniques

Type conversion and validation

Environment variables are e’er strings, require explicit conversion for other data types. Implement robust conversion logic to handle various scenarios.

Import osmium from type import optional def get_built_env(name:STRr, default:builtl = fal)   > bbuilt" convert environment variable to boolean. " vValue= oOSenviron.get(name,'' )lower ( (return value in (' true',' 1',' yes',' on' ) )f get_int_INT(name: str,STRfault: optional[int INT none )  )  ional[int ]: INTonv"  environment variable to integer. " value = ValuevirOS.get(name ) if va)e is none: return default try: return int(valueINTexcept)alueerrorvalue errorefault def get_list_env(name: str, sepaSTRor: str =',' STR > li): convert e" ronment variable to list. " value = os.enValue.geOSname,'' ) return [ i)m.strip ( ) for  Strip( value.split(separator ) if item.str) ( ) ] - u Strip(amples debug = get_bool_env('debugbuiltport = get_)t_env('port',INT00 ) allowed_host)= get_list_env('allowed_hosts' ))

Configuration classes and data structures

Organize environment variables use configuration classes for better maintainability and type safety. This approach centralize configuration management and provide clear documentation of require variables.

Import oxygen from data classes importdata classs from type import optional @dataclass clasdatabase configiURLurSTRstr pool_sizINTint = timeoutsoINT int = 30 @classmethod def from_CLS)ls ): retuCLSc( URLrl OSo Environon['databaURLurl' ], pool_sizeINTiOS(os.environ.gedB'db_pool_size',)0 ), timeout INTnOSos.environ.getdBdb_timeout', ) ) @dataclass classapp configg: secret_keySTRtr debugbuiltol databasdatabase configAPI api_key: optioSTR[str ] = none @classmethod def from_CLS)ls ): retuCLSc( ( secret_key OSo Environon['secret_key' ], debug = os.environ.get('debug',' false').low( ( ) =' true', database database configig.from_e( ( )APIpi_key OSos.environ.getAPIpi_ke) ) - initialize configuration config =app configg.from_en(( )

Security best practices

Protect sensitive information

Environment variables contain sensitive data require special attention. Ne’er hardcode secrets in source code, avoid log environment variables, and use secure methods for variable transmission in production environments.

Implement variable validation to ensure required secrets are present before application startup. Create startup checks that verify critical environment variables exist and contain valid values.

Import OS import says def validate_required_env_vars( ):" validate that all require environment variables are set. " rRequiredvars = [' secret_key',' database_uURL,' aAPIkey' ] missing_vars = [ ] for var in required_vars: if not oOSenviron.get(var ) missing_vars.append(var ))f missing_vars: print(f"mismissedquire environment variables: {','.join(missing_vars )) " " ys.sayst(1 ) )call during application startup validate_required_env_vars ( )(

Environment specific configurations

Different deployment environments require different configuration values. Implement environment specific variable loading to handle development, staging, and production scenarios efficaciously.

Import OS from dot env import loaddot envv def load_environment_confi(( )"  load environment specific configuration. " Env = OS.environ.get('environment',' development') env_file = {' development':'.env.development',' staging':'.env.stage',' production':'.env.production' } - load base.env file load_ddot env'.env') - load environment specific file env_file = env_files.get(env )if env_file and osOSath.exists(env_file ))load_dotdot envv_file, override = true ))rint(f"loaloadnfiguration for { env } environment " )" ad_environment_config ( )(

Integration with popular python frameworks

Django configuration

Django applications benefit importantly from environment variable configuration. Use Django environ Or build in Os. Environ Call in your settings.py file to manage configuration dynamically.

- settings.py import OS from path lib import path - build paths inside the project base_dir = path(__file__).resolve().parent.parent - security settings from environment secret_key =OSs EnvironnDjangogo_secret_key' ] debug = os.environ.getDjangogo_debug',' false').lowe(( ) =' true' allowed_hosts =OSs.environ.get(Djangoo_allowed_hosts',')).split (',') - database configuration databases = {' default': {' engine':' django.db.backends.pPostgreSQL,' name': oOSenviron.get('ddBname' )' user': osOSnviron.get('dbdBser' )) password': os.OSviron.get('db_dBssword' ),)host': os.eOSiron.get('db_hdBt',' localhost' ),')ort': os.enOSron.get('db_podB',' 5432' ), })

Flask application setup

Flask applications can leverage environment variables for configuration management through the build in config system or custom configuration classes.

Import oxygen from flask import flask app = flask(__name _) - load configuration from environment variables app.config['secret_key' ] = oOSenviron.get('flask_secret_key' )app.config['debug' ] = os.environ.get('flask_debug',' false').lower ( (=' true' app.config['database_urlURL = os.OSviron.get('database_urlURL )alternative: configuration class approach class config: secret_key = os.eOSiron.get('flask_secret_key' ) s)alalchemybase_uri = osURIvirOS.get('database_url' ) sURLl)emalchemydifications = false app.config.from_object(config ))

Deployment and production considerations

Container environment variables

Docker containers require specific approaches for environment variable management. Use Dockerfile env instructions, docker compose environment sections, or runtime e flags to set variables.

- Dockerfile from python:3.9 - set default environment variables env python path=/app env flask_app = app.py - copy application code copy. /appworkerr /app - install dependence run pip install   requirements.txt - expose port expose 8000 - start application cmd [ "" thon ", " " .py " ]"

Docker compose files provide convenient environment variable management for multi container applications:

- docker compose.yml version:' 3.8' services: web: build:. Environment: debug = false database_urURL postgresql://user: pass@db:5432 / mymy appecret_key=${secret_key } env_file:  env.production ports:   "" 00:8000 " "  dBage: postPostgresenvironment:   p grPostgresmdBpp my appPostgres = user postgPostgresword=${db_password }

Cloud platform integration

Cloud platforms provide native environment variable management through their respective interfaces. AWS elastic beanstalk, Heroku, google cloud platform, and azure all offer web base configuration panels for environment variable management.

These platforms typically support both web interface configuration and command line tools for programmatic variable management. Many besides integrate with secret management services for enhanced security of sensitive configuration data.

Troubleshoot common issues

Variable not find errors

Miss environment variables cause common application failures. Implement comprehensive error handling and validation to provide clear feedback when variables are unavailable.

Import OS import logging.basicconbasic config log. info ) Info) = logging.getloggeget logger_ ) def )t_required_env_var(name: str )   STR): get STRu"  environment variable with error handling. " value = os.eValuen.gOS(name ) if value ) none: logger.error(f"required environment variable' { name }' not find " ) raise en" onmenterrenvironment errorremissedronment variable: { name } " ) return " ue def debug_environment ( ): " print (vir" ent information for debug. " logger.info("environment variables ( non sensitive(:non-sensitive)= " path',' pythonpath',' envipython path debug' ] for var in safe_vars: value = os.environ.get(vaOS' not set' ) logger.info(f")ar }: { value } " )"

Platform specific challenges

Different operating systems handle environment variables otherwise, potentially cause cross-platform compatibility issues. Windows use different path separators, case sensitivity vary between systems, and shell specific syntax can cause problems.

Address these challenges by implement platform aware code, use python’s Os. Path Module for path operations, and testing applications across target platforms during development.

Environment variable configuration in python applications provide essential flexibility for manage application settings, credentials, and deployment specific values. Master these techniques to build more secure, maintainable, and deployable python applications that adapt seamlessly to different environments and requirements.