A calendar your apps can point at, and a booking link people outside the company can use. A confirmed booking lands in your calendar with a proper invite.
For anybody who books meetings with people outside the company and is tired of a scheduling tool that knows nothing about the customer. Your booking page offers the times you really have free, with more than one window a day and closed days where you need them. Calendars you already keep in Outlook or Google come in one way without connecting an account, so busy means busy. And because the calendar is ordinary records, an app can point at a meeting the same way it points at a person.