Hi @truevladdracul,
Thanks for reaching out!
In order to create a booking form on WPForms, you will need either our Google Calendar addon or one of our connector addons: Zapier or Make.
As these addons are part of the paid version of WPForms, could you please drop us a line through our contact page when you get the chance? You’re welcome to just include a link to this post, if you’d prefer to do that.
I apologize that we’re not able to respond to paid version questions here in the WordPress.org support forums for the free version, but I really appreciate your help!
However in the meanwhile, I would be happy to clarify your question.
Currently we don’t have the feature to avoid double booking at the same date slot. I’ve made a note of the feature request and we’ll keep it on our radar to be reviewed as we plan out our roadmap for the future.
However, if you have a Pro license or higher, you can use this workaround:
- Install the Calculations and Form Locker addons.
- Add a Single Line Text field to your form.
- Go to the field’s advanced settings and enable calculations. Then, click the “Insert Field” button, and select the Date field.
- Next, enable the Require unique answer setting in the field’s advanced settings of the Single Line Text field.
If a user tries to book a previously used date, a validation alert will be displayed.
Thanks 🙂