Mark McNeece of 365i

Environment Indicator adds a prominent visual indicator to the WordPress admin bar showing the current site environment. This high-visibility indicator helps prevent accidental changes on production sites by making the environment instantly recognizable to logged-in users.
Perfect for developers, agencies, and teams managing multiple environments (development, staging, production) across different sites.
<h4>Key Features</h4>
Smart Environment Detection 
* Automatically detects environment using WordPress core constants (<code>WP_ENVIRONMENT_TYPE</code>) 
* Supports popular hosting providers: WP Engine, Pantheon, Kinsta, Flywheel 
* Legacy Bedrock constant support (<code>WP_ENV</code>) 
* Subdomain-based heuristics (dev.example.com, staging.example.com) 
* Manual override option for custom setups
Customization Options 
* Custom Colors – Match your branding or personal preferences for each environment 
* Custom Labels – Rename DEV/STAGING/LIVE to LOCAL, UAT, PRODUCTION, or anything you prefer 
* Role-Based Visibility – Control which user roles can see the indicator (great for client sites)
Visual Enhancements 
* Admin bar label (always visible) 
* Full admin bar background coloring (high-visibility option) 
* Browser tab prefix – instantly identify environments across multiple tabs 
* Top border in wp-admin screens 
* Admin footer watermark 
* Dashboard widget showing environment status and system information
Export/Import 
* Export settings as JSON to deploy across multiple sites 
* Import settings from JSON file 
* Perfect for agencies managing client sites with consistent configurations
Multisite Compatible 
* Full support for WordPress multisite installations 
* Network-wide settings when network-activated 
* Per-site settings when activated on individual sites
<h4>How It Works</h4>
Detection runs in this order:
<ol>
<li>WordPress core constant: <code>WP_ENVIRONMENT_TYPE</code></li>
<li>Legacy constant: <code>WP_ENV</code></li>
<li>Hosting provider constants (WP Engine, Pantheon, Kinsta, Flywheel)</li>
<li>Subdomain patterns (dev, staging, test, qa)</li>
<li>Default to LIVE if no detection</li>
</ol>
You can always override automatic detection and manually select the environment.
<h4>Perfect For</h4>
<ul>
<li>Developers – Never accidentally deploy to the wrong environment</li>
<li>Agencies – Manage multiple client sites with consistent environment indicators</li>
<li>Teams – Everyone instantly knows which environment they’re working in</li>
<li>Managed Hosting – Works out-of-the-box with WP Engine, Pantheon, Kinsta, and Flywheel</li>
</ul>
<h4>Zero Impact on Visitors</h4>
The indicator only displays for logged-in users. Public visitors see no performance impact or visual changes.
<h3>Development</h3>
Development of this plugin happens on GitHub: https://github.com/BSolveIT/environment-indicator
Bug reports and feature requests are welcome!

365i Environment Indicator

Displays a color-coded DEV, STAGING, or LIVE indicator in the admin bar to prevent accidental changes on production sites.

Chris Allen

Poodle Plugins

This plugin makes it easy to distinguish between your local development site, and your live site. 
I created this because I often use a local duplicate of my live site, for development, with the same DB, and the same URL.
I needed a quick & easy way of distinguishing between my live and development sites at a glance. This plugin acheives that in the simplest way possible.
There are settings for colour, positioning and the text displayed on the badge. It is also possible to add a link onto the badge.

WP Dev Flag

Shows a floating badge on the front end, to visually distinguish your development site from production.

365i Environment Indicator vs WP Dev Flag