Google and other manufacturers have recently been subject to a lot of criticism mainly due to the way they utilize user’s data. Unwanted collection of data, targeted ads, customized search results are all a part of this.

With the growing concerns for privacy on the rise, FOSS apps have become quite popular. They are open source apps that have their source code made public which ensures that no shady behavior is going on in the background.

If you have been on the hunt for FOSS apps, then we have the perfect guide for you. Here are some of the most popular and reliable FOSS apps that are currently available on the Google Play Store. All of these apps have their source code posted on GitHub which you can check out yourself.

Browser alternatives

1. DuckDuckGo

DuckDuckGo is a world-renowned search engine for its privacy-focused operation. The DuckDuckGo browser has been developed with the same sense of online privacy in mind.

The app allows you to evade trackers which helps reduce the amount of data that is shared with private advertisers. You can also enjoy enhanced encryption, and best of all, DuckDuckGo gives you a brief rating about each website’s privacy policy. This informs you how much data a website is gathering from you.

Google Play rating: 4.7 stars (370,000+ reviews) | Downloads: 10,000,000+ | In-app purchases: No | Ads: No

Download: DuckDuckGo

2. Firefox Preview

Firefox Preview is a new experimental browser by Firefox that utilizes GeckoView. This enables it to perform twice as fast when compared to native browsers and comes with different features to increase your productivity.

The browser also has a tracking protection feature that automatically denies tracking requests to different websites on the web. Additionally, you also get the option to create to-do lists, perform multiple tasks on different devices, bookmark your most used actions and a lot more.

Google Play rating: 4.1 stars (10,000+ reviews) | Downloads: 500,000+ | In-app purchases: No | Ads: No

Download: Firefox Preview

3. Firefox Lite

Firefox Lite is another privacy-focused browser that is open source and lightweight on your phone’s resources. This browser has an install size of 5.7MB only.

The browser has a dedicated turbo mode, advanced private browsing and a data saver mode as well. Moreover, it comes with proprietary features including shopping deals, travel discoveries and free games that can help you pass the time. The Firefox Lite also has a Night mode that helps reduce the strain from your eyes.

Google Play rating: 4.4 stars (64,000+ reviews) | Downloads: 1,000,000+ | In-app purchases: No | Ads: No

Download: Firefox Lite

Dialer Alternative

4. Koler

Koler is a free open source alternative to your native dialler app. It does not collect any data and has an open-source code available on GitHub. The app has a minimalistic design and a swipeable interface which makes it easier to get used to it.

It resembles a stock Android dialer app but without all the bloatware. If you have been worried about your call data, then Koler is definitely the app for you.

Google Play rating: 3.5 stars (50+ reviews) | Downloads: 5000+ | In-app purchases: No | Ads: No

Download: Koler

Contact App Alternative

5. Simple Contacts Pro

Simple Contacts Pro is a lightweight open source app that has been quite popular in the FOSS community. This app supports importing and exporting of contacts, has in-built support for Vcard and has an in-built dialler too.

Moreover, the app is capable of providing you with contact suggestions based on your usage history and even has a full-fledged editor to edit all your contacts.

Google Play rating: 4.4 stars (700+ reviews) | Downloads: 10,000+ | In-app purchases: No | Ads: No

Download: Simple Contacts Pro

Messaging Alternatives

6. Signal Private Messenger

Signal is a private messaging app that uses end to end encryption to secure your conversations. It allows for seamless communication and even has the ability to make voice and video calls. It does not have any advertisements and has its source code publicly available on GitHub which means no trackers as well.

Additionally, the app has support for in-built stickers as well as a dark mode to compliment the new Android Q UI. And if you are someone who regularly shares pictures with their friends, then Signal has an in-built picture editor for you too.

Google Play rating: 4.6 stars (410,000+ reviews) | Downloads: 10,000,000+ | In-app purchases: No | Ads: No

Download: Signal Private Messenger

7. QKSMS

QKSMS is a great alternative to your native messaging app. It has an intuitive UI, amazing design and best of all it is free and open source. You can fully customize the app and select your choice of color depending on your theme and preference.

It also supports per contact notifications and comes with an in-built night mode. Moreover, it has a spam filter as well as the ability to blocklist numbers. QKSMS is also compatible with TalkBack and the Samsung Voice Assistant which makes it a great choice for people that are physically challenged.

Google Play rating: 4.3 stars (13,000+ reviews) | Downloads: 500,000+ | In-app purchases: Yes | Ads: No

Download: QKSMS

Calculator Alternative

8. Calculator by Xlythe

Calculator by Xlythe is an open-source alternative to your stock Android calculator. It has a simple 4 function UI that can be expanded with advanced settings depending on your preference.

The calculator can also remember your last calculation and allows for real-time graphing. What’s more, the Calculator by Xlythe even has a dedicated home screen widget and full-fledged support for Android Wear as well.

Google Play rating: 4.3 stars (28,000+ reviews) | Downloads: 5,000,000+ | In-app purchases: Yes | Ads: No

Download: Calculator by Xlythe

Calendar Alternatives

9. Etar

Etar is a simple lightweight alternative to your native calendar app that has its source code freely available on GitHub. Like your traditional app, Etar has a monthly, weekly and daily view to sort all your appointments.

You can also sort the calendar based on your agenda entries which is a pretty nifty feature. It has support for both dark and light themes and does not require a network connection to operate. Moreover, Etar has the ability to sync with third-party services like Google Calendar which makes the migration process simple and hassle-free.

Google Play rating: 4.2 stars (337+ reviews) | Downloads: 10,000+ | In-app purchases: No | Ads: No

Download: Etar

10. Simple Calendar Pro

Simple Calendar Pro is a feature-packed free and open source calendar app for Android that does not require an internet connection to operate. It does not have in-built ads and features an intuitive UI design that is easy to navigate and operate.

It has a dedicated home screen widget and supports .ics imports and exports as well. Customizable themes, CalDev support, easy import and export, scheduled notifications, snooze functionality and a lot more make Simple Calendar Pro one of the best alternatives for the stock calendar app that are currently available on the market.

Google Play rating: 4.7 stars (3,000+ reviews) | Downloads: 50,000+ | In-app purchases: No | Ads: No

Download: Simple Calendar Pro

Clock Alternative

11. Simple Clock

Simple Clock is a great alternative for your original clock app. It is completely free and has its source code hosted on GitHub. The app has the ability to show different time zones and comes with an in-built widget for your home screen.

Simple Clock also allows you to set specific days for an alarm, customize vibration and ringtone, condition snooze timings and even add a custom alarm label. There are no in-built ads in Simple Clock and the app comes with a customizable UI.

Google Play rating: 4.0 stars (314+ reviews) | Downloads: 10,000+ | In-app purchases: No | Ads: No

Download: Simple Clock

Gallery Alternative

12. Simple Gallery Pro

Simple Gallery Pro is a paid open-source alternative that helps replace your stock Gallery app. It comes with tons of features including a photo editor, search functionality, intuitive gestures, security vault and more.

The app has the ability to open different types of formats including the likes of RAW, SVG, GIF, etc. You can also create slideshows, add filters to your photos, sort them using different variables and even recover deleted content.

Additionally, you can protect your photos and app using a password, pattern or a fingerprint lock depending on your preference.

Google Play rating: 4.7 stars (37,000+ reviews) | Downloads: 100,000+ | In-app purchases: No | Ads: No

Download: Simple Gallery Pro

Note App Alternatives

13. Orgzly

We all like taking notes, and Orgzly makes that a simple and intuitive experience thanks to its minimalistic UI. It has the ability to take notes and manage to-do lists.

You can even store notebooks in plain text format on the app and later have it sync to your desired location be it an SD card or a cloud service like Dropbox. The app is completely free and has its source code freely available on GitHub.

Google Play rating: 4.6 stars (1,000+ reviews) | Downloads: 50,000+ | In-app purchases: No | Ads: No

Download: Orgzly

14. Joplin

Joplin is another freely open-sourced note-taking app that is currently available on the Play Store. It can take notes, create to-do lists and even add images to your heart’s desire.

Joplin also has the ability to search your notes for a specific keyword which is a handy feature when you are unable to find something important. It is fully compatible with OneDrive and Dropbox which allows you to wirelessly sync your notes to the cloud.

Google Play rating: 4.4 stars (1,000+ reviews) | Downloads: 50,000+ | In-app purchases: No | Ads: No

Download: Joplin

Keyboard Alternative

15. OpenBoard

Most of the personal data that is used by companies to target you are derived from your keyboard application. OpenBoard can help you change that. OpenBoard is a completely open-source and free keyboard alternative.

It has tons of customizability including themes and emojis that can be set according to your aesthetic preference. Unlike other open-source alternatives, OpenBoard does not depend on Google Binaries and even has support for spelling correction.

Google Play rating: 4.3 stars (100+ reviews) | Downloads: 1,000+ | In-app purchases: No | Ads: No

Download: OpenBoard

Other FOSS Apps

16. Retro Music Player

Retro Music Player is a feature-packed FOSS application that features an intuitive design and a minimalistic interface. It has a light and dark theme and even a black theme for AMOLED displays. The app supports gapless playback, album covers, lyrics on the screen, operating timer, tag editor and much more.

You also get the ability to select from 10 different now playing things and queue and reorder your playlist on the fly depending on your mood. Additionally, Retro Music Player has native support for 30 different languages and even comes with its own home screen widget and lock screen controls.

Google Play rating: 4.7 stars (41,000+ reviews) | Downloads: 1,000,000+ | In-app purchases: Yes | Ads: No

Download: Retro Music Player

17. TrebleShot (File Sharing App)

TrebleShot is a great open-source file-sharing alternative that is completely free and does not require a network connection to operate. It allows for seamless transfer of files and has the ability to pause and resume transfers.

You can share large files and multiple kinds of content at the same time. Additionally, you can also share files with multiple devices at the same time provided they all have TrebleShot installed. It has a lightweight design which makes it a great alternative for older devices.

Additionally, TrebleShot can also scan for devices on the same network which gives you the ability to seamlessly transfer files between two new devices.

Google Play rating: 4.7 stars (200+ reviews) | Downloads: 10,000+ | In-app purchases: Yes | Ads: No

Download: TrebleShot

18. AntennaPod

AntennaPod is a FOSS podcast manager that comes with its own in-built podcast player as well. You can sync the app to various podcast services and even get your daily dose of entertainment from paid sources like iTunes & BBC.

AntennaPod also allows you to download and queue episodes based on your preferences and even has the ability to import RSS and Atom feeds. In terms of playback, you are allowed to change the speed, chapters and even set a timer.

Google Play rating: 4.7 stars (26,000+ reviews) | Downloads: 500,000+ | In-app purchases: No | Ads: No

Download: AntennaPod

19. VLC

VLC is a popular open-source media player both on mobile as well as desktop platforms. It comes with tons of features and has its source code readily available on GitHub. Some popular features include the likes of automatic local storage scans, categorizing files, surpassing absolute volume, gesture controls and more.

VLC supports all file types including the likes of .mkv, .mp4, .avi, .mov and a lot more. It even has support for external and embedded subtitles and Teletext. You can even adjust the aspect ratio of your media which is a great feature in today’s world of edge to edge smartphone displays.

Google Play rating: 4.4 stars (1,000,000+ reviews) | Downloads: 100,000,000+ | In-app purchases: No | Ads: No

Download: VLC

20. Alarmio (Paid)

Alarmio is a paid open-source alarm app that has a lightweight open-source design and tons of features. It has an alarm clock, a timer, and a stopwatch to fulfill all your time tracking needs.

You can repeat alarms, set a custom ringtone, set reminders for your routine and even choose a custom background image for your alarm. It comes in a dark and light theme which can be synced to your sunset and sunrise time using location data.

If you have been on the hunt for a simple yet powerful FOSS alarm app, then you should definitely give Alarmio a try.

Google Play rating: N|A stars ( N|A reviews) | Downloads: N|A| In-app purchases: No | Ads: No

Download: Alarmio

21. Waistline Calorie Counter

The waistline calorie counter is a FOSS alternative to your traditional food tracking app. It has the ability to keep a diary of your food intake as well as a column to track the variations in your weight over time. The app does not require a network connection which means that all your data is stored locally on the device. You can export this data anytime you desire.

Additionally, it also comes with an in-built barcode scanner which will help you pull up relevant information on the food product at hand. One thing to note here is that you will have to add an exception for the app in your device’s data cleaner in order to prevent the loss of your data. Many users have reported the loss of data after regular cleaning of the device.

Google Play rating: 3.9 stars (20+ reviews) | Downloads: 500+ | In-app purchases: No | Ads: No

Download: Waistline Calorie Counter

22. Flym News Reader

Flym is a great newsreader that is completely open-source and does not contain any ads. It can fetch news stories from your favorite blogs and websites for a more optimized viewing experience.

The app supports offline reading and allows you to create a list of your favorites as well. Flym is a trusted newsreader that has great reviews on the Play Store and allows for OPML list import and export which makes the process of switching over to Flym quite simple and easy.

Google Play rating: 4.2 stars (450+ reviews) | Downloads: 10,000+ | In-app purchases: No | Ads: No

Download: Flym News Reader

23. Cythara

Cythara is a great app for all music enthusiasts. It has a minimalistic interface that allows you to tune various musical instruments using the same app.

It supports chromatic tuning and has a color-coded interface that helps you achieve the perfect pitch. The app is able to display differences between -60 & 60 cents. Most importantly, it does not contain any ads and has its source code freely available on GitHub.

Google Play rating: 4.9 stars (10+ reviews) | Downloads: 500+ | In-app purchases: No | Ads: No

Download: Cythara

24. Kiss Launcher

Kiss is a lightweight launcher for your Android device that is completely free and open source. It is optimized for battery drain, comes with smart search ability and weighs in at only 535KB in total.

It has support for custom themes and even allows you to change icons using various packs that are currently available on the Play Store. The main advantage of using KISS is that it is an actively supported project that has millions of users around the globe.

Google Play rating: 4.5 stars (2,000+ reviews) | Downloads: 100,000+ | In-app purchases: No | Ads: No

Download: KISS Launcher

25. Proton VPN

Proton VPN is one of the few free VPN services currently available on the market that does not put your personal data at risk. It does not record your browsing history, does not display intrusive ads, collected data is not up for sale and moreover, there are no usage limits!

This means that you can download as much as you want. You get strong encryption, multi-protocol support, DNS leak protection, split tunneling and a lot more. This is one of the only free VPNs on the market that will not put your data at risk. Keep in mind that free users can enjoy only free servers that are currently available only in Japan, US & Netherlands.

Google Play rating: 4.2 stars (1,000+ reviews) | Downloads: 100,000+ | In-app purchases: No | Ads: No

Download: Proton VPN

26. PDF Viewer Plus

Our last choice is the PDF Viewer Plus, this open-source application has a simplistic interface and a minimalistic design.

It allows you to open .pdf files no matter where they are located, be it on the web, on your local storage or in another app. You can share .pdf files using this app and even enjoy multiple different choices of themes.

Google Play rating: 4.5 stars (570+ reviews) | Downloads: 10,000+ | In-app purchases: No | Ads: No

Download: PDF Viewer Plus

What did you think about our list? Did you find a favorite app? Let us know in the comments section below.