Calendar integration platforms let you connect event data between your systems - booking tools, CRMs, email platforms, and personal calendar apps (Google, Apple, Outlook).

AddEvent - calendar engagement and distribution

AddEvent specializes in the outbound side of calendar integration: getting your events from your system into your users' personal calendar apps. Via the AddEvent API, you can create events programmatically and distribute them at scale. Connects to email marketing tools (Mailchimp, HubSpot, Marketo, Salesforce), websites, and any platform via Zapier. Best for companies that want to engage audiences via their calendars.

Zapier / Make (Integromat)

No-code automation platforms that connect calendar apps to thousands of other services. Common flows: new Calendly booking triggers an AddEvent event creation; new Eventbrite registration creates a Google Calendar event. Best for: teams that want to automate calendar workflows without writing code.

Cronofy

Calendar API platform specifically for reading and writing to Google Calendar, Outlook, and Exchange. Used by scheduling and booking tools that need two-way calendar sync. Best for: developers building scheduling features that need to read availability from users' calendars.

Nylas

Developer-focused calendar and email API with unified access to Google, Outlook, Exchange, and iCloud. More enterprise-focused than Cronofy. Best for: product teams building full-featured scheduling into applications.

Google Calendar API / Microsoft Graph API

Native APIs for their respective calendar platforms. Free to use; require developer implementation. Best for: teams building direct integrations with Google or Microsoft ecosystems.

Choosing the right platform

• Distributing events to your audience's calendars: AddEvent
• Two-way sync and availability reading: Cronofy or Nylas
• No-code automation between apps: Zapier or Make
• Native Google/Microsoft integration: Google Calendar API / Microsoft Graph