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This guide applies to:

  • Basic Edition
  • Plus Edition
  • Pro Edition
  • Business Edition


This guide will help you understand how Simply Schedule Appointments loads the time slots in the booking calendars and what you can do to improve your loading speeds.

If you’re seeing that the time slots are never loaded — infinite loading screen — please visit our other troubleshooting guide on this topic.

The Cache and How Your Availability is Loaded

Calculating availability can be very CPU intensive. We have multiple layers of caching built into the plugin to make it perform well, but depending on how you have your site and plugin set up, you can still result with slow loading times.

Whenever someone books an appointment, parts of the cache has to be rebuilt (which requires CPU). This operation has to calculate all the available time slots based on your appointment type rules, Google Calendar exclusions, and your existing bookings.

Causes for Slow Loading Times

  • Slow hosting – your server doesn’t have enough processing power
  • A lot of available time slots — I’m looking at you 10 minute intervals 👀
  • Using the Capacity feature
  • Large number of booked appointments
  • Complex custom rules set in Scheduling Options
  • A lot of personal events in Google Calendar

How to Improve Load Times

We’ve seen SSA run in a wide variety of scenarios without any issue, this includes sites that have hundreds of simultaneous visits and bookings. If you’re experiencing slow loading speeds with the booking calendars, the number one place to look to is the website host.

We hate to point fingers, but if you plan to have a lot of availability and expect a lot of customers to be booking on your site you must have adequate hosting. If your server doesn’t have enough resources and processing power, this should be your first step.

Use the Google PageSpeed Insights tool to find suggestions on how to improve your site performance.

Other Adjustments

Changing to the Weekly view instead of the Monthly view. Since this loads a smaller range of times, the plugin doesn’t have to rebuild such an extensive cache.

Move the scheduling app to a page other than the homepage. This makes it so that every visit to the site isn’t causing the SSA calendar to load. 

Purge Old or Abandoned Appointments. If you have thousands of old appointments in your database, you can delete all of them and see a small improvement in performance (~10%).

Still stuck?

File a support ticket with our five-star support team to get more help.

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