ExpandOps

Access Code Lite lets you require a simple URL parameter code (e.g. ‘?access_code=enter123’) before visitors can view your site. 
Simply share the private access link (e.g. https://example.com?access_code=enter123) that the plugin generates to any user who you wish to grant access. 
Ideal for development, staging, previews, or private sharing without complex authentication.
Features: 
– Set a custom access code from the plugin settings page. 
– Code can be 3–12 characters, letters and numbers only. 
– Session persistence (default): visitors only need to enter the code once per visit. 
– Logged-in users, WordPress login, password reset, admin, AJAX, and cron are always allowed.
Important: Access Code Lite is not a security plugin. 
It does not encrypt, hide, or protect sensitive data. It only adds a simple URL parameter check and should be used for low-risk scenarios like development, staging, or preview access. 
Do not rely on this plugin to secure private or confidential information.
More persistence options (cookies, tokens, etc.) will be added in future versions.

Access Code Lite

Restrict site access with a simple URL code parameter and grant access using private link sharing. Ideal for sites in development or maintenance.

Whodunit

Jb Audras

This plugins provides custom admin bar colors to differentiate environments (staging, preprod, production). It’s really easy to use and developer-friendly.
The plugin provides a settings screen which several options:
<ul>
<li>choose between several color predefined schemes.</li>
<li>use a favicon to better differentiate your environments in your browser’s tabs.</li>
<li>add a custom message in your admin bar, like “Production website”, “staging version” or whatever your want.</li>
<li>choose the user roles that will see the color scheme (other roles will see the default admin bar).</li>
</ul>
It also offers few PHP constants you can use in your <code>wp-config.php</code> file (see Frequently Asked Questions below).
Since WordPress Core will probably deprecate alternate admin color schemes in mid-term, this plugin is meant to be use by those who rely on colors to know is they are in staging, preproduction or production environment.
Last but not least, all provided color schemes are accessibility-ready!

Contextual Adminbar Color

OMG this is what I need.
I actually use the alternate colors, but I don't like to change the good "blacky" interface ;)
So, this is the best option ever.
And since the alt colors will disappear (soon?), it's a good idea to use this to prevent wrong wabsite updates and tons of wasted hours trying to figure "why this is not updating? HO CRAP I AM ON THE PRODUCTION SITE *phone rings* "hey, client… well listen… you won't believe me ha ha ha :|"

This is what I need

Perfect plugin that allows me to easily differentiate my various environments.

THX !

Great !!!

Really enjoy this plugin.
It’s simple and well integrated with WordPress admin UI.

I really like the optional configuration through wp-config.php.
After configuring it once in wp-config.php, I won’t ever need to reconfigure because it doesn’t loose settings on importing settings (eg. staging <-> production).

Great job @audrasjb!

Simple and very usefull!

Such a great helper! It gives me the safety to know exactly which environment I work on without having to worry. 
Sometimes things look just alike in your DEV, STAGE and PROD environment. And with this little plugin, it is immediately obvious which environment you work in.
And it also works on WP 5.6 - just checked...

Makes my life much better knowing exactly where I am

Use custom admin bar colors and favicons to differentiate your environments (staging/prod)

Access Code Lite vs Contextual Adminbar Color