Let people book appointments from your availability and connected calendars.
Individuals plan free forever for 1 user (Cal.com branding); teams $12/user/month.

Notes, tasks & docs
Offer appointment booking and manage availability on your own server.
Offer appointment booking and manage availability on your own server.
Self-hosted appointment booking engine with multi-service and multi-provider scheduling. Open-source web-based appointment scheduler for customer booking, staff management, and business services without commercial booking software fees.
Limitations not yet documented. For TidyCal: run customer appointment booking, service/provider availability and Google Calendar synchronisation on your own server. Free GPL software; hosting, database administration, backups and email delivery can cost extra. This is a self-managed booking workflow, not TidyCal’s automatic video-meeting links, AI assistant, payments or agency suite. For YouCanBookMe: Run appointment booking for services and providers with Google Calendar synchronisation on your own server. Free GPL software; hosting, database, SMTP and maintenance may cost extra. Not YouCanBookMe’s managed multi-calendar connections, Apple/Microsoft calendar integrations, SMS, video-meeting or CRM automation suite.
Each comparison covers the workflow described above, rather than every paid feature.