Cal.com

Cal.com is open-source Calendly with unlimited bookings on the free tier. Self-hostable, 70+ integrations, and no revenue cut from your paid bookings. If you're an indie hacker selling consulting or coaching, Cal.com is the scheduling tool that won't eat into your margins.

Calendly is the polished market leader with superior UX and more integrations — but the free tier limits you to one event type and paid plans start at $10/month. SavvyCal has better UX for complex scheduling. TidyCal (AppSumo) is a cheap lifetime deal with limited features.

Use Cal.com if you want full scheduling functionality without per-booking fees, care about data ownership, or need to embed scheduling into your own product via the API.

The catch: the "Other" license (AGPL with commercial exceptions) means self-hosting modifications require source disclosure. The self-hosted setup requires Node.js, PostgreSQL, and isn't a quick deploy. The free hosted tier is generous but the UI isn't as polished as Calendly's. And if you don't need self-hosting or API access, Calendly's simpler UX might serve you better.