Calendly

Online scheduling platform that lets invitees book meetings based on real-time availability, removing back-and-forth email. Connects up to six calendars, syncs with video conferencing tools, and exposes shareable links or embeddable widgets for websites and apps.

Trusted by more than 100,000 organizations, including 86% of Fortune 500 companies. Differentiates with a broad ecosystem: 100+ integrations for CRM, recruiting, marketing, and productivity tools, plus a full developer API for embedding and automation. Calendly offers API v2 for scheduling data, an Embed API for in-app booking, and webhooks for real-time event notifications.

Key capabilities:

• Calendar sync with real-time availability across up to six connected calendars
• Event types with custom durations, buffers, and scheduling rules
• Embeddable scheduling pages and links for websites and email
• REST API v2 and OAuth 2.1 for third-party integrations and custom apps
• Webhook API for automation triggers on booking and cancellation
• 100+ integrations with Zoom, Slack, Salesforce, HubSpot, Stripe, Zapier, and others

Teams use it for sales discovery calls, recruiting screens, customer success check-ins, and education or coaching sessions. Developers embed booking flows into products, automate follow-ups via webhooks, and pull scheduling analytics through the API.