FOSS apps: free and open source

Free and open-source software: the source code is public under an open licence.

1298 apps

KashCal

All your calendars in one app: iCloud, CalDAV, device and ICS.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Works offline
- No account
- Android only
Google Play Aurora Store F-Droid IzzyOnDroid GitHub Zapstore
Tuta Mail

End-to-end encrypted email, from Germany.
- Communication
- FOSS
- Free
- In-app purchases
- No ads
- No tracking
- iOS
- Android
- Linux
App Store Google Play Aurora Store F-Droid Flathub Zapstore
Proton Mail

End-to-end encrypted email from Switzerland.
- Communication
- FOSS
- Free
- In-app purchases
- No ads
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Snap Store Flathub Zapstore
Proton Drive

End-to-end encrypted cloud storage for files and photos.
- Productivity
- FOSS
- Free
- In-app purchases
- No ads
- iOS
- Android
- Windows
- macOS
App Store Google Play Aurora Store Zapstore
Thunderbird

Free, open-source email, calendar and chat for the desktop.
- Communication
- FOSS
- Free
- No ads
- Windows
- macOS
- Linux
Flathub Snap Store
Signal

End-to-end encrypted messages and calls, run by a non-profit.
- Communication
- FOSS
- Free
- In-app purchases
- No ads
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Flathub Snap Store Zapstore
Molly

A hardened, independent fork of Signal for Android.
- Communication
- FOSS
- Free
- Android only
GitHub Zapstore Accrescent
Firefox

Mozilla’s independent, open-source web browser.
- Internet
- FOSS
- Free
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Flathub Snap Store
Firefox Focus

A private browser that forgets everything when you close it.
- Internet
- FOSS
- Free
- No ads
- iOS
- Android
App Store Google Play Aurora Store
Mozilla VPN

Mozilla’s subscription VPN, built on WireGuard.
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Flathub
Bitwarden

Open-source password manager for every device.
- Security & privacy
- FOSS
- Free
- No ads
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Mac App Store GitHub Flathub Snap Store Zapstore
Bitwarden Authenticator

Two-factor codes, free and separate from your passwords.
- Security & privacy
- FOSS
- Free
- No ads
- iOS
- Android
App Store Google Play Aurora Store GitHub Zapstore
Brave

Chromium-based browser that blocks ads and trackers by default.
- Internet
- FOSS
- Free
- In-app purchases
- iOS
- Android
- Windows
- macOS
- Linux
App Store Google Play Aurora Store Flathub Snap Store Zapstore
Nextcloud Desktop

Sync files between your computer and your Nextcloud.
- Productivity
- FOSS
- Free
- No ads
- Windows
- macOS
- Linux
Flathub
Auditor

Checks with hardware attestation that a phone’s OS has not been tampered with.
- Android only
GrapheneOS App Store GitHub
GrapheneOS Camera

A private camera app with QR and barcode scanning.
- Multimedia
- FOSS
- Free
- Android only
GrapheneOS App Store GitHub Zapstore
GrapheneOS PDF Viewer

A PDF viewer that needs no permissions.
- Productivity
- FOSS
- Free
- Android only
GrapheneOS App Store GitHub Zapstore
Element Desktop

Matrix chat on the desktop: Windows, macOS and Linux.
- Communication
- FOSS
- Free
- Windows
- macOS
- Linux
Flathub Snap Store
Mullvad Browser

A privacy browser built with the Tor Project, without the Tor network.
- Internet
- FOSS
- Free
- Windows
- macOS
- Linux
Flathub
Tor Browser

Browse privately and anonymously over the Tor network.
- Internet
- FOSS
- Free
- No ads
- Android
- Windows
- macOS
- Linux
Google Play Aurora Store Flathub Zapstore
Onion Browser

A free, open-source Tor browser for iPhone and iPad.
- Internet
- FOSS
- Free
- iOS
- iPadOS
App Store
Orbot

Tor for your whole phone, as a VPN.
- Security & privacy
- FOSS
- Free
- No ads
- iOS
- Android
App Store Google Play Aurora Store Zapstore
0x54ask

Todo.txt manager. Offline, works with Syncthing. Fork of SimpleTask Cloudless
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
Agenda Tech

Private offline calendar: encrypted, zero network, encrypted backups.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid GitHub Zapstore
Autasker

A simple but robust task manager available on Android, Windows and Linux.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid GitHub Zapstore
Axichat

Replace your email, messenger, and calendar with one app.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid GitHub Zapstore
Birday - Birthday Manager

A simple yet useful birthday manager. Birday is free and ad-free! 🥳
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid IzzyOnDroid GitHub Zapstore
Birthday Adapter

See birthdays and other events from your contacts in your calendar.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid GitHub Zapstore
Birthday Calendar

Creates birthday events from all other calendar's data
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid
Birthday Countdown

An App counting down to your next birthday!
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
BirthDayDroid

This application will help you remember all the birthdays of your friends
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid
C
CalEF (Calendar Entry Formatter)

Create and send Appointment-Confirmation-Message from Android-Calendar-Entry.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid
C
Calendar Color

Change the calendar color
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
Calendar Import-Export

Import, Export & Backup your calendars using ics files
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
Calendula: Calendar

A Material 3 Expressive calendar for Android with no network access.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid Zapstore
CalSync - Local Calendar Sync

Sync local calendars offline. Free, open source, no account needed.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid GitHub Zapstore
CalSync - Notification Calendar Sync

Sync notification time info to calendar automatically
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid IzzyOnDroid GitHub Zapstore
Casio G-Shock Smart Sync

Add smart functions to your Casio square BT G-Shock Watch.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid GitHub Zapstore
Clock31

Clock + Calendar combo widget for Android
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid IzzyOnDroid
Concert Diary

Concert Diary recreates a personal diary for concerts and festivals.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
Date-a-base

Your Personal Assistant for Every Special Occasion.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
DeuFeiTage

Find the German public holidays per state and year
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid
Did I Take My Meds?

An app to manage and track medication doses
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid GitHub
Etar - OpenSource Calendar

Etar is a material designed open source calendar, for everyone!
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid Zapstore
EteSync - Secure Data Sync

Secure, private and end-to-end encrypted calendar, contacts and tasks sync
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid GitHub Zapstore
Everyone's Timetable

Looking for a prof's or friend's school timetable? Look in here!
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid
Flux

Stay organized. Stay focused. Stay in Flux.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
F-Droid IzzyOnDroid GitHub Zapstore
Fossify Calendar

Securely plan, schedule, and set reminders with our private calendar app.
- Calendar
- FOSS
- Free
- No ads
- No tracking
- Android only
Google Play Aurora Store F-Droid IzzyOnDroid GitHub Zapstore