Zero-dependency PHP class that loads .env files in a layered, mode-aware fashion.
Auto-detects dev vs prod from the hostname — no manual configuration needed.

Namespace: uniko · PHP: 8.0+ · Version: 1.0.0

Loading happens in two layers:

1. .env — base/shared config, always loaded first (required)
2. dev.env — loaded on top when on localhost prod.env — loaded on top when on a remote server

Values in the overlay always win over the base .env.

The mode is never set manually — it is determined automatically at construction time from $_SERVER['HTTP_HOST']:

* In CLI context (cron, migrations), falls back to getenv('APP_MODE'), defaulting to dev if not set.

project/
├── .env          ← shared base values
├── dev.env       ← dev overrides  ← add to .gitignore
├── prod.env      ← prod overrides ← add to .gitignore
└── src/
    └── EnvLoader.php

⚠️ Never commit dev.env or prod.env — they typically contain credentials.

No Composer required. Just drop the file in and require it:

require_once __DIR__ . '/src/EnvLoader.php';

$loader = new \uniko\src\EnvLoader(__DIR__);
$result = $loader->load();

// $result['mode'] → 'dev' or 'prod'
// $result['env']  → $_ENV array (merged)

$loader->isDev();    // true on localhost
$loader->isProd();   // true on remote server
$loader->getMode();  // 'dev' | 'prod'

Global constants are also defined automatically after load():

MODE    // 'DEV' or 'PROD' (uppercased string)
ISDEV   // true | false
ISPROD  // true | false

// Via $_ENV
$host = $_ENV['DB_HOST'];

// Via getenv()
$host = getenv('DB_HOST');

// Via constant (key uppercased)
echo DB_HOST;

Pass true to remove all loaded keys from $_ENV and $_SERVER after constants are defined:

$result = $loader->load(unsetENV: true);

Use setReplace() to inject runtime values into .env placeholders before constants are defined:

# .env
APP_URL=https://{{DOMAIN}}/app

$loader->setReplace(['{{DOMAIN}}' => 'example.com'])
       ->load();

// APP_URL → 'https://example.com/app'

No external library. Supports:

After load(), constants are defined globally from the merged environment:

Constants are only defined if not already defined — pre-existing constants are never overwritten.

If the base .env is missing, a RuntimeException is thrown.
Overlay files (dev.env / prod.env) are optional and silently skipped if absent.

try {
    $result = $loader->load();
} catch (\RuntimeException $e) {
    error_log($e->getMessage());
}

• PHP 8.0+
• No external dependencies

Copyright © 2026 uniko.ca - MIT