pureenv 0.4.0

Typed environment variable parsing for Python. Zero dependencies. Pure stdlib.

pureenv

Typed environment variable parsing for Python. Zero dependencies. Pure stdlib.

---

The Problem

Every Python project ends up writing this:

PORT   = int(os.environ.get("PORT", 8080))
DEBUG  = os.environ.get("DEBUG", "false").lower() == "true"
DB_URL = os.environ["DATABASE_URL"] # KeyError with no helpful message

Manual casting. No validation. Cryptic error. Every. Single. Project.

The solution

from pureenv import env # .env file auto-loaded if it exists

PORT   = env("PORT",                default="8080") # no casting needed  
PORT   = env.int("PORT",            default=8080)   # or typed
DEBUG  = env.bool("DEBUG",          default=False)
DB_URL = env.str("DATABASE_URL",    required=True)

Typed. Validated. Clear errors when something is wrong.

Install

pip install pureenv

Usage

Create a .env file in your project root:

DATABASE_URL=postgres://localhost/mydb
DEBUG=true
PORT=8080

Then just import and use - no setup needed:

from pureenv import env

# strings - without casting (return str)
APP_NAME  = env("APP_NAME",     default="myapp")

# explicit str
DB_HOST = env.str("DB_HOST", default="localhost")

# numbers
PORT  = env.int("PORT",    default=8080)
RATIO = env.float("RATIO", default=0.5)

# booleans - accepts "true/false", "1/0", "yes/no", "y/n", "on/off"
DEBUG = env.bool("DEBUG", default=False)

# required - raises a clear error if missing
DB_URL = env.str("DATABASE_URL", required=True)

# grouping related env variables
with env.prefix("DB_"):
    DB_HOST = env("HOST", default="localhost") # reads DB_HOST
    DB_PORT = env("PORT", default="5432")      # reads DB_PORT
    DB_NAME = env("NAME", default="mydb")      # reads DB_NAME

Why not environs or python-dotenv?

	pureenv	python-dotenv	environs
Typed casting	✅	❌	✅
Zero dependencies	✅	✅	❌
Required validation	✅	❌	✅
Loads .env file	✅	✅	✅
Auto-loads .env	✅	❌	❌
Prefix grouping	✅	❌	✅

✅ Auto-loads means no setup needed — just from pureenv import env and your .env is loaded automatically.