WordPress Plugin Blacklist

WordPress is a great platform, mostly because of the HUGE number of plugins available.

Unfortunately, some developers do not test their plugins for performance or scalability. Where possible, and by popular demand, we are writing performance enhancements for every plugin possible and adding them to Scalability Pro.

This plugin blacklist identifies plugins to avoid due to poor performance at scale. If you are the author of one of these plugins, please get in touch and I can help solve the scalability issues inherent in your plugin.

Plugins that prevent page caching

These cache-busting plugins should be avoided because if you use them, you cannot cache your pages.

• Yith Wishlist – if a page is cached, the next user will see the last users wishlist – if anyone knows a good Ajax-based Wishlist alternative, let me know
• WooCommerce recently viewed products widget – if a page is cached, the next user sees the previous uses recently viewed products. There’s an alternative Ajax-based widget you can use included with Scalability Pro.
• Simple Ajax Chat – it spits out user-specific Javascript inside a PHP page. This means if you cache the page, the 2nd user will be able to talk to admin as if they are the first user…

Plugins that are just plain slow

• Ewww Image Optimiser – ugh, I don’t know where to start – IIRC it fetches every image on every page load – avoid at all costs! Use SmushIt instead and/or Imsanity)
• Booster.io – the WooCommerce ‘Booster’ – it added a good 5 seconds pageload in PHP (CPU maxed out) for my client who was using it
• WPML – sloooow. Use Q-translate instead, way faster at scale

More to follow – I’ll soon be releasing Scalability Lite which will give the index creation aspects of performance optimisations from our Scalability Pro plugin. At the same time, we’ll provide the option for users to submit their before & after performance measurements (automated by the plugin) to us so we can improve WordPress performance.

Once the data from this starts to come in, I’ll fully populate this list with plugins to avoid and which alternative plugins you can use that pass my scalability tests.

I’ve enabled comments for this page, so let me know which awful and awesome plugin experiences you’ve had at scale.