Software Alternatives, Accelerators & Startups

ProtonCalendar

A secure calendar designed to be paired with the equally secure ProtonMail service.

Top 8 Open-Source Alternatives to ProtonCalendar

ProtonCalendar
Nextcloud Calendar Simple Calendar Tutanota SOGo Calendar Lock PEA FullCalendar Cal.com Spark Mail

Summary

The top open-source alternatives to ProtonCalendar are Nextcloud Calendar, Simple Calendar, and Tutanota. One of the criteria for ordering this list is the number of mentions that products have on reliable external sources. You can suggest additional sources through the form here.
  1. The Calendar app is a user interface for Nextcloud's CalDAV server.
    Pricing:
    • Open Source

    #Email #Appointments and Scheduling #Calendar 4 social mentions

  2. A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
    Pricing:
    • Open Source

    #Email #Appointments and Scheduling #Calendar 99 social mentions

  3. Get your encrypted mailbox for free.
    Pricing:
    • Open Source

    #Email #Enterprise Communication #Email Clients 181 social mentions

  4. 4
    SOGo is groupware server with a focus on scalability and open standards.
    Pricing:
    • Open Source

    #Email #Email Service Provider #Email Clients 1 social mentions

  5. Calendar Lock PEA is an encrypted desktop calendar with a day, week and month view. The shown calendars are never stored unencrypted on your disk, but exist only in the RAM. Platform-independent, Open Source, no installation or registration required.
    Pricing:
    • Open Source
    • Free

    #Appointments and Scheduling #Calendar #Security & Privacy

  6. FullCalendar is an open-source JavaScript event calendar.
    Pricing:
    • Open Source

    #Appointments and Scheduling #Calendar #Appointment Scheduling 15 social mentions

  7. Cal.com (formerly Calendso) is the open source Calendly alternative.
    Pricing:
    • Open Source

    #Productivity #Appointments and Scheduling #Open Source 57 social mentions

  8. Spark helps you take your inbox under control. Instantly see whatโ€™s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
    Pricing:
    • Open Source

    #Email #Calendar #Enterprise Communication 32 social mentions

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