Cal.com is an open-source scheduling and appointment booking platform that revolutionizes how professionals manage their calendar. A direct alternative to Calendly, Cal.com stands out with its open-source approach, flexibility, and competitive pricing. The platform lets you create customized booking pages, manage multiple event types (one-on-one, collective, round-robin), and automatically sync your Google, Outlook, and Apple calendars. With built-in AI, Cal.com can automate scheduling, suggest optimal time slots, and even handle rescheduling. Cal.com offers advanced features like automated workflows (email/SMS reminders), integrated payments (Stripe), team management with intelligent routing, and a complete API for custom integrations. The platform integrates with 100+ applications via Zapier and offers native integrations with Zoom, Google Meet, Microsoft Teams, and more. The free plan is generous for individual users, while Team and Enterprise plans add team management, advanced workflows, and priority support. Self-hosting is possible thanks to the open-source license.

HubSpot is a complete CRM platform integrating marketing, sales, customer service, and CMS. With its Breeze AI, it automates prospecting, email writing, and predictive lead scoring.