What are IMAP and CalDAV?
IMAP and CalDAV are standard protocols: the first for reading your email, the second for syncing your calendars. Any compatible app can connect to them, whatever the provider. Your messages and appointments therefore stay portable from one service to another, with no closed format. The topic continues in chapter 5 of my book, Vivre sans Google.
Information verified on July 13, 2026
At home, any lamp plugs into any socket. Nobody forces you to use the electricity provider’s lamp. IMAP and CalDAV play that role for your data: they are the standard sockets of email and calendars. IMAP lets an app read your mailbox, CalDAV keeps your calendars in sync, whatever service sits behind them.
What does that change in practice? Everything. If your provider speaks IMAP and CalDAV, you freely choose your mail or calendar app, on your computer and on your phone. Above all, you can move out: a new compatible service picks up your messages and appointments without breaking anything. It is the opposite of a closed format, where your data only leaves if the owner allows it.
This technical detail looks dry. Yet it decides your freedom: a service that respects standards lets you go, a service that ignores them holds you back. The guide to leaving Google Calendar shows what this looks like in practice.
Where it plays out: chapter 5 of the book organizes the migration of your calendar and contacts, and the Calendar and contacts category lists the services that play by the standards.
This topic is chapter 5 of my book
It answers these questions, among others:
- how do you move your calendars without losing shares and invitations?
- maximum encryption or the freedom to choose your app: how do you decide?
- and what hides in twenty years of accumulated calendar entries?
Forthcoming 22/10/2026 from Éditions Eyrolles
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Tech jargon, translated
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