Top 12 Open-Source Alternatives to Lightning Calendar

Product categories

APIs Appointment Scheduling Appointments and Scheduling Calendar Calendar And Scheduling Email Email Clients Email Service Provider Enterprise Communication Productivity SMTP Server Self-hosted Email

Summary

The top open-source alternatives to Lightning Calendar are Simple Calendar, Calendar Lock PEA, and Nextcloud Calendar. 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.

Simple Calendar Landing Page
1

Simple Calendar

A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Pricing:
- Open Source
#Calendar #Appointments and Scheduling #Email 99 social mentions
Calendar Lock PEA Landing Page
2

Calendar Lock PEA

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
#Calendar #Appointments and Scheduling #Encryption
Nextcloud Calendar Landing Page
3

Nextcloud Calendar

The Calendar app is a user interface for Nextcloud's CalDAV server.
Pricing:
- Open Source
#Calendar #Appointments and Scheduling #Email 4 social mentions
Mailspring Landing Page
4

Mailspring

Mailspring is a mail client for Mac, Windows and Linux.
Pricing:
- Open Source
#Email #Email Clients #Calendar 25 social mentions
Compass Calendar App Landing Page
5

Compass Calendar App

Calm calendar for productive people
Pricing:
- Open Source
#Calendar #Calendar And Scheduling #Calendar App
Tutanota Landing Page
6

Tutanota

Get your encrypted mailbox for free.
Pricing:
- Open Source
#Email #Email Clients #Enterprise Communication 177 social mentions
Mail-in-a-box Landing Page
7

Mail-in-a-box

Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.
Pricing:
- Open Source
#Email #Self-hosted Email #Email Service Provider 115 social mentions
iRedMail Landing Page
8

iRedMail

A fully fledged, free email server solution, an open source project (GPL v2).
Pricing:
- Open Source
#Email #SMTP Server #Self-hosted Email 2 social mentions
gsimplecal Landing Page
9

gsimplecal

gsimplecal is a lightweight calendar application written in C++ using GTK2.
Pricing:
- Open Source
#Calendar #Appointments and Scheduling #Audio Recording
Calendar Landing Page
10

Calendar

Calendar app is an online calendar and team scheduling software for people like me and you. We make it easy to schedule appointments on your calendar.
Pricing:
- Open Source
#Appointments and Scheduling #Appointment Scheduling #Meeting Scheduling 2 social mentions
Cal.com Landing Page
11

Cal.com

Cal.com (formerly Calendso) is the open source Calendly alternative.
Pricing:
- Open Source
#APIs #Open Source #Calendar And Scheduling 53 social mentions
Roundcube Landing Page
12

Roundcube

Web-based IMAP email client
Pricing:
- Open Source
#Email #SMTP Server #Email Clients 16 social mentions