Fossify Calendar vs Proton Calendar

Fossify Calendar

• Android users who want a calendar without ads, tracking or sign-up
• People who prefer open-source apps installed from F-Droid
• Keeping a private, local calendar that never leaves the phone

Proton Calendar

• People who want event details kept unreadable to the provider
• Existing Proton Mail users who want invitations handled in the inbox
• Privacy-focused organizations standardizing on Proton's business suite

Fossify Calendar

• Android only; the Fossify project lists Android as its sole platform.
• The app has no sync service or cloud account of its own. Syncing depends on accounts or calendar providers configured on the device.
• Development is funded by donations, and help comes through a public issue tracker and community channels.
• Google Play and F-Droid publish releases on their own schedules, so versions can differ between stores.

Proton Calendar

• Proton Free allows 3 personal calendars; Mail Plus and higher plans allow 25.
• Calendar sharing and booking pages need a paid plan, and Mail Plus and Proton Unlimited include only 1 booking page.
• Calendar has no subscription of its own: paid features come with Mail Plus, Proton Unlimited or a business plan.
• Desktop use is through the Proton Mail app for Mac, Windows and Linux, a 14-day trial on free accounts; the Linux app is labeled beta.

Fossify Calendar

Five calendar views

Day, week, month, year and event-list views, with event filters to narrow what is shown and controls for color, theme and display.

Recurring events and reminders

Events take times, durations, reminders and advanced repetition rules. Reminder sounds, looping audio and vibration can be customized.

Sync through device accounts

Calendar data can sync through accounts or calendar providers set up on the device, such as Google Calendar, Outlook, Nextcloud or Exchange. Fossify runs no sync service of its own.

Import and export

Calendars can be imported from and exported to files, which keeps the data portable and gives a way to back it up or move it to another app.

Holidays, birthdays and anniversaries

Holidays can be imported, and birthdays and anniversaries can be drawn from the phone's contacts if contacts access is granted.

No Internet permission

The app does not request Android's Internet permission, contains no advertising and sends no app data or usage records to Fossify.

Proton Calendar

End-to-end encrypted events

An event's title, description, location and attendees are encrypted on your device. Events received from people on other calendar services are stored with zero-knowledge encryption.

Appointment booking pages

Publish a booking page that shows only the times you choose and syncs with your calendars to prevent double bookings. Confirmed meetings can include a Proton Meet link. Paid plans only.

Calendar sharing

On paid plans, share a calendar by link or by inviting people directly, showing either full event details or only your availability.

Works with Proton Mail

Send invitations from a Proton Mail address, manage them without leaving the inbox, and add events received by email, such as flights or meetings, to the calendar.

Recurring events and reminders

Events can repeat daily, weekly, monthly or on a custom pattern, with several reminders or email alerts each. Views switch between day, week and month.

Import and calendar subscriptions

The Easy Switch tool imports existing calendars from other providers, and you can subscribe to calendars that other people keep on a different service.

Fossify Calendar

• Fossify Calendar$0

  The complete app, installed from Google Play or F-Droid, with no ads or in-app purchases. Donations are optional.

Proton Calendar

• Proton Free$0

  3 personal calendars, end-to-end encryption, and sending and receiving invitations.

• Mail Plus$3.99

  per month, billed every 12 months ($47.88); $4.99 billed monthly

  25 personal calendars, calendar sharing and 1 booking page, plus 15 GB of storage and 10 email addresses.

• Proton Unlimited$9.99

  per month, billed every 12 months ($119.88); $12.99 billed monthly

  The same calendar features as Mail Plus, bundled with 500 GB of storage and Proton's VPN, password manager and cloud storage.

• Workspace Standard$12.99

  per user / month, billed every 12 months ($155.88)

  Business suite with 25 calendars and 25 booking pages per user, 1 TB of storage per user and 15 custom email domains.

• Workspace Premium$19.99

  per user / month, billed every 12 months ($239.88)

  Everything in Workspace Standard, plus 3 TB of storage per user, 20 custom email domains and data retention policies.

• EnterpriseCustom

  All Proton services in a customizable package with a dedicated account manager; priced through sales.

Fossify Calendar

No public discounts listed.

Proton Calendar

• Annual discount

  20% off Mail Plus on the 12-month plan

  Proton's pricing page lists Mail Plus at $3.99 a month when billed every 12 months ($47.88), against $4.99 billed monthly. Proton Unlimited is $9.99 instead of $12.99.

• Education

  Student discount for the first 12 months

  Students verified through Student Beans get 50% off Mail Plus and 62% off Proton Unlimited for the first 12 months; the plan then renews at the regular price.

• Nonprofit

  Reduced pricing for registered nonprofits

  Registered nonprofits can request discounted pricing on Proton's business plans from the sales team. No fixed percentage is published.