# Choose a calendar provider

Provider support depends on the operation, permissions and access channel.

Source: https://docs.getridian.com/integrations/providers/
Language: en
Reviewed: 2026-09-20

## Compare the connection types

| Provider | Connection | Important boundary |
| --- | --- | --- |
| Google Calendar | OAuth | Calendar access does not grant Tasks, Contacts or Gmail access |
| Microsoft 365 / Outlook | OAuth | Tenant rules, shared rights and partial consent affect access |
| Apple iCloud | CalDAV app-specific password | Existing series can be read; CalDAV series writes are unsupported |
| Other CalDAV services | Provider credentials / preset | A preset is not a live compatibility guarantee |
| ICS feed | Feed URL | Read-only source; no AI event writes |
| Hosted Exchange | EWS pilot | Requires a real compatible EWS setup, not just an M365 license |

## Choose by workflow

For cross-provider sync, both source and destination must support their assigned roles. For AI access, compare the specific tool and provider, not just whether the account can connect. For a developer integration, check the currently published REST or MCP contract separately.

A writable provider calendar can still reject a meeting edit, a recurring-series change or a conflicting update. Per-event capabilities are more specific than account-level access.

## Connect the right identity

Use the identity that actually owns or can access the intended calendar. Aliases and a primary mailbox are not interchangeable provider identities. For a shared or room calendar, check the provider's permission and booking policies as well as Ridian.

Read the [Google/Microsoft guide](https://docs.getridian.com/integrations/google-microsoft/), [CalDAV guide](https://docs.getridian.com/integrations/caldav/) or [ICS/EWS guide](https://docs.getridian.com/integrations/ics-exchange/) before starting.