Cal.com

Cal.com is an open-source scheduling platform that lets individuals and businesses set up booking pages for meetings, similar in end-user function to well-known proprietary scheduling tools, but built entirely in the open so it can be self-hosted, customized, and extended by anyone rather than depending on a single closed vendor's roadmap and data practices. Users connect their calendar, define availability rules and meeting types, and share a booking link that lets others schedule time directly based on real-time availability, automatically handling time zone conversion, calendar invites, and reminder notifications without back-and-forth email scheduling. Because it's open-source, developers and companies can inspect, modify, and extend Cal.com's codebase directly, and its API-first architecture means scheduling functionality can be embedded directly into another company's own product, which has made Cal.com a common choice for platforms that need to offer native scheduling as a feature rather than linking out to a separate third-party booking tool. Self-hosting options give organizations with data residency or compliance requirements full control over where scheduling data lives, while a hosted cloud version exists for individuals and teams who don't want to manage that infrastructure themselves. Its workflow automation and routing forms support more complex scheduling scenarios, like routing a booking to a specific team member based on form responses. Cal.com is used by individuals, agencies, and platforms building scheduling into their own products.