Proton Calendar vs Teamup

Proton Calendar is a calendar service for managing events, invitations, and recurring schedules on Android and iOS. Event titles, descriptions, locations, and invited people are protected with end-to-end or zero-knowledge encryption. A free Proton account costs nothing and allows up to 3 calendars. Paid Proton Mail plans allow up to 25 calendars, with calendar sharing by link to other calendar services on the web. Users can send invitations and add events from Proton Mail; appointment scheduling updates availability and adds confirmed meetings. The service supports scheduling links and video meetings, and notifications can arrive through desktop browsers or mobile devices. Calendar import and export are available on paid plans. Subscriptions purchased through proton.me renew automatically, and users can switch plans at any time; upgrades receive prorated credit. Proton is incorporated and headquartered in Switzerland and follows Swiss privacy laws.

Teamup Calendar is a cloud-based group calendar for organizing schedules, resources and teams. It offers 12 views, including year and table formats, and nine permission levels. Calendars can be shared through links without requiring recipients to have accounts. Events support custom fields, images and file attachments, and can also be shared as individual event pages. Teamup lists integrations including its API, iCalendar feeds, Slack, Microsoft Teams, Trello and Zapier; it provides iOS and Android apps and one-way calendar sync. The free plan allows five sub-calendars and five users. Paid plans start at $12/mo billed yearly, with a 3-day trial. Teamup says it is ISO/IEC 27001 certified and compliant with EU GDPR, and describes encryption for connections, stored data and backups. Its production services are hosted on AWS, with user content redundantly stored in Oregon and Ireland. Private-server hosting is unavailable.