Is s2Member compatible with caching plugins?
Comet Cache™, WP Super Cache, W3 Total Cache, and Others
s2Member has been thoroughly tested against all of the most popular caching plugins for WordPress. These include, but are not limited to: Comet Cache™, WP Super Cache, W3 Total Cache, and WP Rocket. When dynamic content is processed by s2Member, all of the appropriate runtime constants are defined by s2Member; i.e., the flags needed to keep it fully compatible with caching plugins for WordPress.
Comet Cache™ Developed by the Creators of s2Member Pro
If you definitely want to use a caching plugin for WordPress, but you're not sure which would be the best, go with Comet Cache™. It's super easy to install, highly effective, and it was developed by the creators of s2Member; i.e., it works in complete and total harmony with all s2Member features—without any additional configuration needed whatsoever.
Tip: Comet Cache has a unique ability to cache logged-in users too, which is highly effective whenever it runs alongside the s2Member Pro application; keeping WordPress fast even when a user is logged in as a member. Very impressive!
Avoid Object Caching Plugins Warning
Page caching is highly recommended. Object caching—not so much. In particular, the W3 Total Cache plugin is known to cause problems with the WordPress Transient API whenever Object Caching is enabled. If you choose to install W3 Total Cache and run this alongside s2Member, that's fine! Just remember NOT to enable the Object Cache; i.e., leave that part off please.