Shifter is a static site generator SaaS. So some plugins for WordPress (e.g. contact forms, e-commerce, site searches) won't work. When generating the static files, Shifter will automatically disable unsupported plugins. Here's a list of what's unsupported along with some alternatives.

For more information, read our blog post about this topic.

Comments in WordPress need to be switched to the following external services:

Here's documentation that can help you integrate your site with Disqus.

BBpress needs to be replaced with something like Zendesk and the documentation (with images) to do this is here.

BuddyPress or other membership plugins which work dynamically with PHP won't work on Shifter.

Plugins for commerce, such as WooCommerce, Easy Digital Downloads, or others that work dynamically with PHP won't work. Shopify will work fine because they process data outside of your static site.

Our WP Serverless Forms plugin to work with ContactForm7! Please check below document for setting up with Basin!
​Using WP Serverless Forms WordPress Plugin with Basin
​

We recommend that you to use Algolia (document here) or Google Custom Site Search (document here).

You (and we!) love the Rest API, but it is not for Shifter. REST API will work when you are logged in to your admin dashboard, but not when end-users are on the static site. There's no alternative for this, unfortunately.

Shifter will not cover these kind of plugins, and no alternatives.