Calendars & Scheduling UIs

Calendar / scheduler components

• ★ Schedule-X — modern, modular, framework-agnostic (React, Vue, Svelte, Solid, Preact, Angular). Date picker + scheduler views (day, week, month, agenda). The default for new projects.
• FullCalendar — venerable, big feature set; commercial license required for some advanced features (resource timeline) but the core is MIT.
• react-big-calendar — long-standing React calendar; date-fns / Moment / dayjs adapters.
• Toast UI Calendar — open source; rich features, less active than the above.
• Calendar by Bryntum — commercial; gorgeous; Gantt + Scheduler.

Date pickers (single-day or range)

• ★ react-day-picker — used by shadcn/ui's Calendar.
• react-aria DatePicker / DateField — Adobe; best a11y story.
• MUI X Date Pickers — if you're on MUI.
• vue-cal, v-calendar — Vue equivalents.

Time pickers / scheduling logic

• @internationalized/date — locale-aware date types (used by react-aria).
• Temporal API polyfill — see Dates & Time.
• rrule.js — recurrence rules for "every other Tuesday" etc.

Scheduling-as-a-service (Calendly alternatives)

• ★ Cal.com — open-source Calendly competitor; embeddable, self-hostable, generous free tier.
• SavvyCal — paid; great UX; embed available.
• Calendly — paid, the incumbent.
• Microsoft Bookings, Google Calendar Appointments — bundled with workspace.

Calendar protocol / sync

• ical.js / node-ical — parse/generate iCalendar.
• ical-generator — generate ICS files for download.
• Davical, Radicale — self-hostable CalDAV servers.
• Nylas, Cronofy — hosted multi-provider calendar APIs (Google + Outlook + iCloud) with free trials.

Pick this if…

• Default new calendar UI: Schedule-X.
• Need long-tail features (resources, Gantt): FullCalendar Premium or Bryntum.
• Date picker only: react-day-picker (with shadcn) or react-aria DatePicker.
• Need a Calendly clone: embed Cal.com or self-host it.
• Sync to multiple calendar providers: Nylas or Cronofy.