If you need to securely share data from your or your company’s Calendly account with an internal or private application that’s not for use by others outside of your company, then use personal access tokens. They are unique and not meant to be shared with public sources or reused across applications.
Testing out Calendly’s API endpoints in a local development environment
Building a reporting dashboard to reflect meetings your company has scheduled
Pushing Calendly event and invitee data into your company’s CRM
If you need to provide a way for Calendly members to securely share their Calendly account data with a public application you’ve built, then use OAuth 2.0.
An application that allows your customers to get easy access to their Calendly event type links to share as they respond to support tickets
An application that creates an agenda each time your customer’s clients schedule a meeting with them
An application that contacts your customer’s Calendly invitees