Cal.com

Cal.com is a scheduling tool in the category that Calendly defined: a bookable link that reads a calendar's availability and writes an event when someone books. It is open source, which is the main difference, and it can be self-hosted so booking data stays on your own infrastructure. The product supports the expected scheduling features: multiple event types, buffers, minimum notice, round-robin distribution across a team, and routing forms that send a booker to the right event based on their answers. It connects to Google, Microsoft, and Apple calendars for availability and to conferencing tools for meeting links. Self-hosting is the reason many teams choose it, and also the main cost. Running the platform means operating a Postgres database, the application, and its background jobs, plus keeping up with releases. Teams that want scheduling to be someone else's operational problem use the hosted plan instead.