Calendar
284 open source Calendar apps
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FOSSGIS 2026 Schedule
APK
Programm zur FOSSGIS-Konferenz am 25. - 28. März 2026 in Göttingen https://www.fossgis-konferenz.de Die FOSSGIS-Konferenz ist im D-A-CH-Raum die führende Konferenz für Freie und Open Source Software für Geoinformationssysteme sowie für die Themen Open Data und OpenStreetMap. Funktionen * Tagesüberblick über alle Programmpunkte * Beschreibung von Veranstaltungen lesen * Veranstaltungen in persönlicher Favoritenliste verwalten * Alle Veranstaltungen durchsuchen und filtern * Favoritenliste exportieren * Alarm für Veranstaltungen setzen * Veranstaltungen in Kalender eintragen * Link zu Veranstaltungen mit anderen teilen * Programmänderungen einsehen * Veranstaltungen bewerten * Integration mit dem Helfersystem, https://helfen.fossgis.de (siehe Einstellungen in der App) * Integration mit Chaosflix https://github.com/NiciDieNase/chaosflix - Android App für https://media.ccc.de, teile Fahrplan-Favoriten mit Chaosflix und importiere sie als Bookmarks 🔤 Unterstützte Sprachen (Programmtexte ausgenommen) * Dänisch * Deutsch * Deutsch, Österreich * Englisch * Finnisch * Französisch * Italienisch * Japanisch * Litauisch * Niederländisch * Polnisch * Portugiesisch, Brasilien * Portugiesisch, Portugal * Russisch * Spanisch * Schwedisch * Türkisch 💡 Inhaltliche Fragen zum Programm kann nur das FOSSGIS-Team beantworten. Diese App stellt lediglich die Programmpunkte zur Verfügung. 💣 Fehlerberichte sind herzlich willkommen, aber achte darauf, dass du erklärst, wie man den Fehler reproduzieren kann. Der Issue-Tracker findet sich hier: https://github.com/EventFahrplan/EventFahrplan/issues 🏆 Die App basiert auf der EventFahrplan-App https://f-droid.org/packages/info.metadude.android.congress.schedule/ für den Kongress des Chaos Computer Clubs. Der Quellcode der Anwendung ist auf GitHub https://github.com/johnjohndoe/CampFahrplan/tree/fossgis-2026 zu finden. 🎨 FOSSGIS-Logo-Design: Jane Eder
F-DroidGitHub
FallASleep - Device sleep timer
APK
Setup a timer between one and 60 minutes. Once the timer runs out, the app will lock your device's screen. Features: Simple and clean designLock screen after 1 to 60 minutesRemembers last timerQuick setting tileNotification to stop, extend or reset timer Permissions: Device admin to lock the screen
F-DroidGitHub
Floating Timer
APK
The Floating Timer app features both a countdown timer and stopwatch that will float on top of other running apps. This app is useful to time activities such as: Exam practice, gaming speed runs (speed-running), gaming boss fights, cooking.Usage:Drag to move timer positionTap to start / pauseDouble tap to resetDrag to trash to exitPremium version unlocks:Simultaneously run more than 2 timers (multiple timers)Change Timer size and colorOpen source: https://github.com/tberghuis/FloatingCountdownTimer
GitHubIzzyOnDroid
Florae
APK
Florae is an open source application that will allow you to keep track of the care of your plants while respecting your freedom and privacy. Set reminders for basic plant care such as watering, pruning, cleaning, fertilizing, spraying, rotating, and transplanting. Consult future plant cares for better planning of your time, adjust the frequency of care alerts and don't forget to water your plants ever again.
F-DroidGitHub
Flux
APK
Flux – Flow Through Your Workspace with Ease Experience the power of continuity and simplicity. Flux helps you stay organized with a modern design and focused workflow. 🎉 Features 📝 Sleek, Minimalistic Design powered by Material UI (Material 3) 🌟 Workspace Templates: Structure your work with custom workspaces 🔐 Biometric App Lock to keep your data secure 🚀 Frequent Updates & Improvements to enhance your flow Stay in control, stay in motion — download Flux and experience seamless productivity.
F-DroidGitHub
Fokus
APK
Fokus is an open source application that combines a todo list and a calendar that can help you manage your school related work and events in one place. It’s fast and beautiful yet simple design that can help you focus on what matters most.Features:Get reminded when a task is nearing its dueGet reminded about incoming eventsAdd attachments to your tasksPersistent notifications for important tasks or eventsNo ads or any trackingOpen Source CodeOn-Device Database
GitHubIzzyOnDroid
Fomodoro
APK
Fomodoro is a simple, customizable Pomodoro timer Android app designed to help you focus and manage your work/break sessions efficiently. The app features a clean UI, dark mode, AMOLED mode, and flexible session settings.Features:Pomodoro timer with customizable focus, short break, and long break durationsAdjustable number of sessions per cycleAuto-start sessions optionDark mode and AMOLED mode supportSimple, distraction-free interfaceVibration feedback for button actionsEasy access to settings and GitHub repository
GitHubIzzyOnDroid
F
Foreground
APK
Foreground is an easy to use task manager app. Designed to be beautiful, simple and unintrusive, Foreground helps you know what needs done without getting in your way. Foreground also supports syncing with Taskwarrior servers. Syncing To set up sync, add your taskwarrior server credentials (provided by your taskd server or a service like inthe.am or FreeCinc) to the settings menu, and enable sync using the toggle. A test will be run to check if the settings are valid, and the enable will stick if the config works. You can also configure automatic syncing in this menu, or click the sync button on the main page to start a sync. Implementation Details Unlike existing Taskwarrior apps for Android, Foreground does not run the taskwarrior binary inside, but rather implements a taskwarrior sync client. This allows for greater device compatibility and simplifies UI development but it can cause issues when syncing if not done correctly. Current Limitations Foreground currently supports most features of Taskwarrior. Notable exceptions involve handling of recurring events and display/editing of User Defined Attributes. Recurring event instances created by other clients will be shown by Foreground, but Foreground does not create recurring event instances of its own at this time. User Defined attributes are preserved internally but are not yet exposed for viewing or editing. These limitations will be resolved in future releases.
F-DroidGitHub
Fossify Calendar
APK
Tired of cluttered calendars and privacy concerns? Fossify Calendar is here to change that. Your open-source powerhouse for managing life, designed with privacy as its core and packed with powerful features to keep you organized. Here's what makes Fossify Calendar different: 🚫 AD-FREE AND PRIVATE: Your events remain yours. No ads, no tracking, no intrusive permissions. ⏰ FLEXIBLE AND CUSTOMIZABLE: Craft events precisely with times, durations, reminders, and advanced repetition rules. 🔄 SEAMLESS SYNCING: Sync effortlessly with Google Calendar, Outlook, Nextcloud, Exchange, and more. 🎨 PERSONALIZE YOUR PLANNER: Set custom sounds, looping audio streams, vibrations, and themes to match your preferences. 🌈 VIBRANT WIDGETS: Brighten your day with beautiful calendar widgets and themes for your home screen. 📅 EFFORTLESS DAY MANAGEMENT: Plan your day with ease, whether you're a busy professional or a family organizer. 🎉 IMPORT CELEBRATIONS: Never miss a birthday or anniversary! Easily import holidays and special dates. 🔍 FILTER VIEWS: Quickly find what you're looking for with event filters. 📆 MULTIPLE VIEWS: Switch between daily, weekly, monthly, yearly, and event views effortlessly. ✨ MATERIAL DESIGN ELEGANCE: Enjoy an intuitive and user-friendly interface with dynamic themes. Plus, Fossify Calendar is open-source! Join the vibrant community on GitHub, contribute to the project, and make it uniquely yours. Download Fossify Calendar now and experience the power of a private and customizable schedule. Explore more Fossify apps: https://www.fossify.org Open-Source Code: https://www.github.com/FossifyOrg Join the community on Reddit: https://www.reddit.com/r/Fossify Connect on Telegram: https://t.me/Fossify
F-DroidGitHubIzzyOnDroid
Fossify Clock Beta
APK
Introducing Fossify Clock – the ultimate timekeeping companion designed to enhance your daily routines and promote better sleep habits. With a multitude of functions tailored to your needs, Fossify Clock seamlessly integrates into your life, offering unparalleled convenience and versatility. ⌚ MULTIFUNCTIONAL TIMEKEEPING: Experience the power of versatile time management with Fossify Clock. From serving as a clock widget to functioning as an alarm clock and stopwatch, this app is your go-to tool for regulating your daily activities and improving your overall lifestyle. ⏰ FEATURE-RICH ALARM: Wake up refreshed with Fossify Clock's comprehensive alarm features. Set multiple alarms with options like day selection, vibration toggle, custom labels and ringtone customization. Enjoy gradual volume increase and a customizable snooze button for a pleasant waking experience. With a user-friendly interface, setting up alarms has never been easier. ⏱️ CONVENIENT STOPWATCH: Track your activities with precision using Fossify Clock's stopwatch function. Measure longer periods or individual laps effortlessly. You can also sort your laps in ascending or descending order. ⏳ PRECISE TIMER FUNCTIONALITY: Stay on top of your tasks with Fossify Clock's versatile timer feature. Customize ringtone preferences, toggle vibrations, and pause countdowns to suit your needs. Whether you're timing cooking intervals, managing study sessions, or ensuring timely breaks, Fossify Clock has you covered with precision and ease. 🌈 CLOCK WIDGET WITH CUSTOMIZABLE FEATURES: Transform your home screen with Fossify Clock's customizable clock widget. Adjust text color, background color, and transparency. Choose between analog or digital clock to suit your style and easily access essential time information at a glance. 🎨 CUSTOMIZABLE INTERFACE AND THEMES: Enjoy a personalized experience with Fossify Clock's material design and dark theme options. Tailor the app to your preferences with customizable colors and themes, enhancing usability and reducing eye strain, especially in low-light environments. 🔒 PRIVACY-FIRST APPROACH: Rest assured knowing your privacy is protected with Fossify Clock's offline operation. Experience maximum privacy, security, and stability without sacrificing functionality or convenience. 🌐 AD-FREE & OPEN-SOURCE: Say goodbye to intrusive ads and unnecessary permissions. Fossify Clock is ad-free, fully open-source, and grants you complete control over your timekeeping experience. Upgrade your time management skills, optimize your routines, and prioritize better sleep with Fossify Clock. Download now and take control of your time like never before. Explore more Fossify apps: https://www.fossify.org Open-Source Code: https://www.github.com/FossifyOrg Join the community on Reddit: https://www.reddit.com/r/Fossify Connect on Telegram: https://t.me/Fossify
F-DroidGitHubIzzyOnDroid
Foto Timer
APK
Foto Timer for Android is a free, open source app that can count and beep. It helps with repeating tasks, such as at the gym. People also use it for developing analogue film, or for meditating. Foto Timer is working with "processes", which define how Foto Timer counts, and how often it beeps. Processes can also be "chained" together, meaning that a process can automatically launch another. There is almost no limit to how complex your timers can be. If you want to see what Foto Timer looks like, take a look at the manual. If you prefer a "how to" approach, learn how to use Foto Timer for Tabata exercises. Foto Timer contains absolutely no AI whatsoever.
F-Droid
Fourth Tools
APK
100% FOSS! Currently available tools: * Calculator * Timer (Stopwatch) * Temporary file hosting Dark mode is fully supported!
F-Droid
French Calendar
APK
Resizable widget which displays the current date and time in the French Revolutionary calendar. The widget supports the following preferences: * Whether to display the current time, or the name of the object for that day of the year (ex: grape). * Calculation method: method used to determine the first day of the year: Either based on the autumn equinox, or the Romme method. * Language of the calendar (limited to just a few languages for now). Other features: * Possibility to share the information about the current date. * The color of the widget is customizable, but by default is different for each month. * You can add the widget to your lock screen (on supported devices). Three widget styles: * Horizontal parchment * Vertical parchment * Minimalist
F-DroidGitHub
Friend Alert
APK
FriendAlert: Keep Your Friendships Thriving, No Matter How Far Apart Life's adventures lead us to friendships that cross cities, countries, and even continents. While these connections add immeasurable value to our lives, keeping them vibrant across distances can be a challenge. Born from this universal struggle, FriendAlert is your go-to solution for keeping those important friendships alive and well. Functions The application offers a simple reminder to remember to contact your friends: you can set how often you want to keep in touch and every time you call a friend you can record that inside the app. If you do not call one of your friends for a time longer than the limit you set, you'll be sent a notification. 🌍 Your Central Hub for Global Friendships Whether your friendships were formed on the playground or during an international journey, FriendAlert functions as your unified platform for sustaining these invaluable bonds. With FriendAlert, neither miles nor time zones can weaken your connections. 🗣️ Foster Authentic Connections: More than Just Check-ins Social media may offer cursory updates about people's lives, but it's no substitute for genuine conversation. FriendAlert encourages you to engage in meaningful dialogues that go beyond the superficial. A Personal Perspective I created FriendAlert with the aim of maintaining contact with the people who matter most to me. While the app's utility can vary, here are some personal guidelines I follow: Use FriendAlert to track those you find you're losing touch with, not the friends you see regularly. Although in-person meetings are irreplaceable, phone or video calls serve as excellent alternatives when that's not feasible. Texting, though convenient, falls short in conveying emotional nuance and should not be your primary mode of communication. Engaging via social media—such as liking photos or commenting—simply doesn’t cut it when it comes to nurturing real friendships. Elevate Your Social Ecosystem FriendAlert emerged from a personal need for an accessible, budget-friendly way to sustain my social circle. While platforms like nouri.ai have their merits, FriendAlert offers a free and user-friendly alternative. Sharing good moments is nice. Let's enrich not just our conversations, but our lives and communities through stronger, more meaningful connections.
F-Droid
GDF HEMA Timer
APK
GDF HEMA Timer is a precise and minimal timer designed for Historical European Martial Arts (HEMA) training. It helps fencers, instructors, and tournament organizers manage timing during drills, bouts, and sparring sessions. Features: - Simple interface with large, readable display - Configurable round and break durations - Audible and vibration alerts for start and end signals - Preset saving for repeated training routines - Works fully offline, with no ads or tracking - Open-source and lightweight This timer is developed by practitioners for practitioners, focusing on reliability and clarity during intense training sessions.
F-DroidGitHub
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GPN 2025 Schedule
APK
Programm App für die Gulaschprogrammiernacht. https://gulas.ch Die Gulaschprogrammiernacht (kurz: GPN) ist ein 4-tägiger Kongress, der vom Entropia e.V. (CCC Karlsruhe) einmal jährlich veranstaltet wird. Der Name ist bei der GPN wörtlich zu nehmen, denn immer wieder schafft es auch ein Haufen Hacker eine große Menge Gulasch zuzubereiten, um die Gäste zu nähren, damit sie gestärkt zum nächsten Vortrag - über Programmierung oder Gesellschaft - oder zum Programmieren ins Hackcenter gehen können. Funktionen: * Tagesüberblick über alle Programmpunkte (Vorträge, Workshop, Lounge) * Beschreibung von Veranstaltungen lesen * Veranstaltungen in persönlicher Favoritenliste verwalten * Alle Veranstaltungen durchsuchen * Favoritenliste exportieren * Alarm für Veranstaltungen setzen * Veranstaltungen in Kalender eintragen * Link zu Veranstaltungen mit anderen teilen * Programmänderungen einsehen * Bewertungen und Kommentare für Vorträge und Workshops hinterlassen * Integration mit dem Trollsystem https://engelsystem.de - Online-Tool für Helfer- und Schichtplanung auf großen Events * Integration mit Chaosflix https://github.com/NiciDieNase/chaosflix - Android App für https://media.ccc.de, teile Fahrplan-Favoriten mit Chaosflix und importiere sie als Bookmarks 🔤 Unterstützte Sprachen (Programmtexte ausgenommen) * Dänisch * Deutsch * Englisch * Finnisch * Französisch * Italienisch * Japanisch * Litauisch * Niederländisch * Polnisch * Portugiesisch, Brasilien * Portugiesisch, Portugal * Russisch * Spanisch * Schwedisch * Türkisch 🤝 Du kannst mithelfen, die App zu übersetzen. Siehe Link hier. 💡 Inhaltliche Fragen zum Programm kann nur das Content-Team der GPN beantworten. Diese App stellt lediglich das Programm zur Verfügung. 💣 Fehlerberichte sind herzlich willkommen, aber achte darauf, dass du erklärst, wie man den Fehler reproduzieren kann. Bitte nutze den Issue-Tracker: https://github.com/EventFahrplan/EventFahrplan/issues. 🏆 Die App basiert auf der EventFahrplan-App https://play.google.com/store/apps/details?id=info.metadude.android.congress.schedule für den Kongress des Chaos Computer Clubs. Der Quellcode der Anwendung ist auf GitHub https://github.com/johnjohndoe/CampFahrplan/tree/gpn-2025 zu finden. 🎨 Logo-Design von Thilo Billerbeck
F-DroidGitHub
GetFlow
APK
GetFlow is an application based on the Pomodoro Technique that helps you stay productive and accomplish your long-term goals. Statistics will give you the motivation to stay focused and show how you improve over time. How It Works 1. Pick a task you want to accomplish. 2. Work on the task for 25 minutes. 3. Take a 5-minute break. 4. After four sessions, take a 20-minute break. Features * Start, pause, skip and stop timer using gestures * Support for short and long breaks * User-created activities such as reading, programming * Support for different timer settings in each activity * Block applications during work * Enable Do Not Disturb and disable Wi-Fi during work * Full screen mode * Keep screen on * AMOLED-friendly * Statistics with an overview, history chart, and activity distribution * Entirely ad-free and open-source * All features available to all users, no in-app purchases * Doesn’t require an internet connection or account registration * Your data is never sent to anyone
F-DroidGitHub
Giant Stopwatch
APK
Sports stopwatch with: giant digits and adjustable theme (color, font, size, spacing, format) control with both on-screen buttons and volume buttons lap-timer delayed-start (with audio 3...2...1... countdown). Free, small, no ads, open source (github.com/arpruss/simplestopwatch). As a bonus, includes a giant number clock (swipe to switch between clock and stopwatch). I made this so I could easily see the time while rock climbing at the gym 50 feet up. It's also useful poolside for swimming, and for other sports where you need to see the time from a distance (or close up, if you want).
F-DroidGitHub
Giggity
APK
Giggity loads xcal/Pentabarf/frab XML files (that contain schedules of conferences/festivals/other events) and lets you browse them in various convenient formats. Preseeded with many events including FOSDEM, CCC, FrOSCon, etc. Giggity lets you organise your visit - select talks to be reminded of (with warnings in case of conflicts) or hide the topics you're less interested in. Schedules are shown in whatever format you like - block schedules, plain timetables, or a clear now-and-next screen on the day itself.
F-DroidGitHub
Goals Tracker 24/7 - timeto.me
APK
The main feature of this app is goals. Tap a goal to start a timer with the remaining time for that goal. Timer is running all the time, 24/7, even for sleep or breakfast. No stop option! To stop the current goal, you have to start the next one. You can add a checklist for goals. Useful for morning/evening routines, work, exercises, etc. This way I control my time and don't forget anything. Try to adapt it to your life. Best regards, Ivan
F-DroidGitHub
G
Goodtime - Minimalist Pomodoro Timer
APK
A minimalist but powerful productivity timer designed to keep you focused and free of distractions. Alternate between focused work sessions and short breaks handled by the app. Get rid of procrastination and improve your time management! ⏳ split your work into sessions of focus and then reward yourself with a break ☕ after more sessions of work, take a longer break Features: * Lightweight and battery friendly * Configurable timer * Pause, skip or add 60 seconds * Detailed statistics * Disable sound and Wi-Fi connection during the work sessions * AMOLED-friendly user interface * Colored labels * Timer styles * Manually add sessions * Edit completed sessions * Backup export and import * Export statistics to CSV * Screensaver mode * Themes * Separate notification sound for work and break * Insistent notifications
F-DroidGitHub
Gradr
APK
Allows students to simply and easily track their grades. Create classes and add grades for each of those classes. Each grade is created with a name and the point value it holds. With this you can calculate the percentage and overall grade for each class. Gradr also allows students to automatically predict how many points they need on their next assignment to get the grade that they desire.
F-DroidGitHub
Grazer Linuxtage
APK
Schedule application for the event Grazer Linuxtage (GLT) The Grazer Linuxtage is an annual two-day conference about open-source, hardware and software. The GLT offers workshops on Fridays and talks and info booths on Saturday on a multitude of topics. Grazer Linuxtage App features: * Upcoming and live events * View program by day and rooms (side by side) * Custom grid layout for smartphones (try landscape mode) and tablets * Read detailed descriptions (speaker names, start time, room name, links, ...) of events * Search through all events * Create your own customized schedule with favorites * Share events by email, twitter, etc. with your colleagues and friends * Reminder for your favorite talks * Offline support (Download the program) * Add events to your personal calendar * Keep track of program changes * Automatic program updates (configurable in settings) * Vote and leave comments on talks and workshops 🔤 Supported languages: (Event descriptions excluded) * Danish * Dutch * English * Finnish * French * German * Italian * Japanese * Lithuanian * Polish * Portuguese (Brazil) * Portuguese (Portugal) * Russian * Spanish * Swedish * Turkish 💡 Questions regarding the content can only be answered by the content team of the Grazer Linuxtage (GLT). This app simply offers a way to consume and personalize the conference schedule. It's Open Source and available under the Apache-2.0 License. https://github.com/linuxtage/EventFahrplan 💣 Bug reports are very welcome. It would be awesome if you can describe how to reproduce the particular error. Please use the GitHub issue tracker https://github.com/linuxtage/EventFahrplan/issues This App is based on the EventFahrplan: https://github.com/EventFahrplan/EventFahrplan
F-DroidGitHub
Guessaday
APK
A trainer for calculating the day of the week of any given date. This app displays a random date and asks you what day of the week that date is. Then it checks your answer. Optionally it measures how long it took you. In the settings you can configure the range for the random date. If you want to learn how to do this calculation, check out on the developer's website!
F-DroidGitHub