Android, which itself is built on open-source principles, has a thriving ecosystem of open-source apps that value transparency, privacy, and data freedom. These apps, which often cost nothing and deliver an ad-free experience, can go toe-to-toe with their proprietary counterparts.
We’ve already covered some of Android’s best open-source apps in a recent guide. But that barely scratches the surface. So, here are some more excellent Android apps that champion transparency.
1
Notesnook
There is much to like about Notesnook. It’s focused on user privacy and security. All your notes are end-to-end encrypted, giving you peace of mind. It’s also available across all major platforms for seamless availability of all your notes. Moreover, you get a rich text editor for composing notes, tons of organization tools, and the ability to set reminders.
You can lock the app behind biometric or password-based authentication. But if some of your notes need extra security, the Private Vault has a second password and double encryption.
You can also import or export your notes, and the paid “Pro” version includes support for automatic encrypted backups.
Joplin is another note-taking app to consider. It has a similar feature set and focuses on security.
2
AntennaPod
AntennaPod is a well-liked podcast manager that gives you access to millions of free and paid podcasts from around the world. You can import your existing podcast library and manage playback according to your preferences. The app supports adjustable playback speeds and automatic podcast downloads.
It also offers decent automation controls, allowing you to control how much battery, storage, and data are used while downloading episodes. Plus, AntennaPod is completely free and lacks advertisements.

Related
The Best Podcast Apps for Android
There’s no shortage of podcast apps in the Play Store, but these are the ones you should check out.
3
Breezy
A fork of the Geometric Weather app, Breezy is a powerful weather app with tons of features and a clean interface. It provides real-time weather conditions, daily and hourly forecasts for up to 16 days, and air quality information. You’ll also get severe weather and rain alerts.
You can choose from dozens of weather sources for different features. Additionally, the app comes with a large selection of widgets for quick access to weather data.
4
LibreOffice Viewer
Although LibreOffice doesn’t provide a full-fledged office suite for Android, its Viewer app is more than enough for most smartphone needs. It can open Microsoft Excel, PowerPoint, and Word documents as well as Open Document Format.
Editing features aren’t available by default, but you can enable Experimental mode to get them. Remember that these features are still being tested and may not work as anticipated.
If you want a full-featured Office suite, the Collabora Office is worth looking into. It’s based on the LibreOffice desktop version, so it has more features, including document editing support, than the LibreOffice Viewer.
5
HeliBoard
HeliBoard is a fully offline Android keyboard based on AOSP and Openboard. It supports multilingual typing, dictionaries, keyboard themes, and a one-handed mode. You can also customize the keyboard layout and access the clipboard history. If you use HeliBoard on a bigger screen, you’ll also get access to a split keyboard.
Glide typing isn’t included by default. However, you can add the feature if you are okay with a closed-source library from Google.
The Futo Keyboard is another excellent keyboard app for FOSS enthusiasts, but it has yet to reach a stable version.
6
Amaze File Manager
If you aren’t happy with the file explorer offered by your phone’s manufacturer, the Amaze File Manager is an excellent replacement. It uses Material Design and has a simple and clean interface. It has all the essentials and supports file encryption and decryption for extra security.
There are no ads, and the app includes a built-in ZIP/ RAR reader, text reader, and database reader. It also supports FTP, FTPS, SMB, and SFTP protocols.

Related
The Best Alternative File Managers for Android
With the right app, managing files can actually be fun.
7
Librera
Looking for an excellent PDF or ebook reader? It’s hard to go wrong with Librera. Although it’s primarily an ebook reader, it works great as a PDF reader. It can handle most ebook formats and lets you tweak the reader interface to meet your needs.
You can also easily manage and organize your ebook library, as the app supports automatic scanning and has a built-in file explorer. Other features include a unique mode for musicians and a speed-reading mode.
If you prefer a simpler reader app, muPDF Viewer is worth considering. It’s not as feature-rich as Librera but can display your PDF, XPS, CBZ, and EPUB files.
8
OSS Document Scanner
The OSS Document Scanner is an excellent app for creating digital versions of paper documents, business cards, and more. It can automatically detect the document from the camera scan and crop out unnecessary material. It also allows you to adjust the corners of the document for better finishing or to fix any app mistakes.
You can scan the documents using your phone’s camera or import them from existing photos on your phone. For security, there is also support for adding biometric or PIN-based authentication. Finally, you can export the scanned documents as PDFs for sharing.
9
LocalSend
If you frequently transfer files between devices, LocalSend is perfect for you. It uses your existing Wi-Fi network to share files between your phone and another device or vice versa. It’s easy to use and has end-to-end encryption for the sanctity and security of your data. It’s also free to use and contains no ads.
You don’t need to register for anything; the only requirement for the app to work is that both of your devices be on the same Wi-Fi network.
If you’re looking for more awesome Android apps, check out our password manager, music player, and digital detox recommendations. For open-source enthusiasts, we also have open-source app guides for iPhone, Mac, and Windows.

Related
9 Open-Source Android Apps You Should Be Using
Thanks to a vibrant developer community, Android users have access to a fantastic selection of open-source apps. Whether you seek transparency, trust, or freedom from locked-down ecosystems, open-source alternatives exist for almost all the essentials most folks need.