Frequently asked questions about Tella
General
What is Tella?
In challenging environments, with limited or no internet connectivity or in the face of repression, Tella is an app that makes it easier and safer to document human rights violations and collect data.
For more information on how to use Tella, visit the Getting Started guide.
Who makes Tella?
Tella is developed and maintained by Horizontal, a human rights non-profit. In addition to developing Tella, Horizontal develops other privacy and security tools, and trains activists, journalists, and human rights defenders in digital security.
Is Tella available on Android?
Yes, Tella is available for Android and can be downloaded directly from the Google Play Store , from our Telegram channel or from this folder, as an APK, to be installed manually. If you need to help to install the app manually you can follow this guide or contact us.
Follow the get quick start guide for Tella users on Android for quick onboarding.
Learn more about How to find and download Tella from the Play Store and How to install Tella manually in our video tutorials.
Is Tella available on F-Droid?
Yes, we publish a version of Tella Android on F-Droid, which we call Tella FOSS. Tella FOSS does not support all features available on Tella Android. For details about which features are available on Tella FOSS, see what features are available on each platform and our release notes page.
All code, libraries, and dependencies in Tella FOSS are entirely Free and Open Source Software (FOSS). Tella FOSS only includes an opt-in privacy-preserving analytics tracker.
Is Tella available on iOS?
Yes, Tella for iOS can be downloaded from the App Store. For details about which features are available for iOS, see What features are available on each platform.
Follow the get quick start guide for Tella users on iOS for quick onboarding.
What features are available on each platform?
| Feature | Android | iOS | Android FOSS |
|---|---|---|---|
| App Lock | Password, PIN, Pattern | Password, PIN | Password, PIN, Pattern |
| Background encryption | ✔️ | ✔️ | ✔️ |
| Backup files to cloud | - Google Drive - Nextcloud - Dropbox | - Google Drive - Nextcloud - Dropbox | Not yet |
| Lock timeout configuration | ✔️ | ✔️ | ✔️ |
| Camera silent mode | ✔️ | Not yet | ✔️ |
| Screen Security | ✔️ | ✔️ | ✔️ |
| Restrict unlocking attempts | ✔️ | ✔️ | ✔️ |
| Edit Media | Crop, Rotate, Flip and Zoom Photos | Crop and Rotate Photos, Trim Audio and Videos, Rotate Video | Crop, Rotate, Flip and Zoom Photos |
| Encryption | ✔️ | ✔️ | ✔️ |
| Encrypted file management | ✔️ | ✔️ | ✔️ |
| Feedback | ✔️ | ✔️ | ✔️ |
| Import files from device | ✔️ | ✔️ | ✔️ |
| Preserve metadata when importing | ✔️ | ✔️ | ✔️ |
| Privacy preserving analytics (opt-in) | ✔️ | Not yet | ✔️ |
| Camouflage | ✔️ | Not possible in iOS | ✔️ |
| Homescreen customization | ✔️ | ✔️ | ✔️ |
| Camera (photos and videos) | ✔️ | ✔️ | Yes but missing zoom, flip camera, enable flash and enable grid |
| Select video resolution | ✔️ | Not yet | Not yet |
| Audio Recorder| ✔️ | ✔️ | ✔️ |
| Open files in Tella| ✔️ | ✔️ | ✔️ |
| Verification mode| ✔️ | Not yet | ✔️ |
| Quick delete| Files, Connections and Tella | Files and Connections | Files, Connections and Tella |
| Quick exit| Locks and close | Locks | Locks and close |
| Share button | ✔️ | ✔️ | ✔️|
| Server connections | - Tella Web
- Uwazi
- Google Drive
- Dropbox
- Nextcloud
- Open Data Kit (Forms) | - Tella Web
- Uwazi
- Google Drive
- Dropbox
- Nextcloud | - Tella Web
- Uwazi
- Open Data Kit (Forms) |
| Nearby Sharing | ✔️ | ✔️ | Soon! |
| Offline data collection | ✔️ | ✔️ | ✔️ |
For more details about each feature see Features.
Is Tella available on desktop?
Yes, Tella is available on desktop, but for the moment can only be used to receive files.
You can download Tella Desktop for Windows, MacOS and Linux. Follow the quick start guide for Tella users on Desktop for quick onboarding.
Do you offer a back-end or repository to store data?
Tella Web is a web app that acts as a repository to store reports submitted by Tella users, including photos, videos, and audio. Learn more about Tella Web here
Note that it is not possible to encrypt and hide files or create reports on Tella Web. These features are only available on the mobile apps. Tella Web is one of the connections available to send the data collected on the Tella app.
Where can I get Tella?
Please refer to the Is Tella available on Android?or to the Is Tella available on iOS? questions depending on the device you own.
How do I become a beta tester for Tella?
- Android: Sign up on the Google Play Store using this link from your Android device or this link from your web browser.
- iOS: Sign up on the App Store opening this link from your iPhone.
What phones support Tella?
Tella is compatible with devices running Android 5.0 or later and iOS 14.0 or later.
Does Tella work on GrapheneOS?
As of December 2024, we haven't been able to test Tella Android and Tella FOSS on GrapheneOS, so we cannot confirm that all features work properly. Some users have reported that the main features (lock, file encryption and management, etc) work properly, but some of the Connections (like Google Drive) do not work. If you use GrapheneOS and you experience a problem, please contact us.
Is Tella free?
Yes, Tella is free to download and use. It will remain free forever.
Tella is also Open Source.
What languages is Tella available in?
Language accessibility is one of our priorities, so we work hard to make Tella available in languages spoken by communities who express the need for Tella.
Currently Tella is available in:
- Arabic
- Azerbaijani
- Belarusian
- Bengali
- Burmese
- English
- French
- Indonesian
- Jingpho
- Kannada
- Karen Sgaw
- Kurdish
- Malayalam
- Ndau
- Persian
- Portuguese
- Portuguese (Mozambique)
- Russian
- Spanish (Latin America)
- Tamil
- Tsonga
- Vietnamese
Read more about Language accessibility in Tella here.
Does Tella work on tablets?
Tella works on Android tablets, but it is currently not available on iPad. Please contact us if iPad support is important to you so that we can make it a priority.
Where can I send my suggestions to improve Tella?
We'd love to hear from you! Please contact us!
Storage
How much storage do I need to install Tella?
The Tella app itself is small:
- 26MB on Android
- 7MB on iOS
The app size will grow depending on the size of the data stored on it. There is an option to configure the quality of the videos taken with Tella (Very high, High, Medium or Low) if users needs to save space. It's also possible to delete the files, photos and videos in Tella to save space.
How much can I store in Tella? What is the storage limit?
There is no specific storage limit for Tella, limits will depend on the system storage space available in your device.
External storage locations (like SD cards) are not currently used by Tella.
Can i backup the data I store in Tella?
Yes, you can, but the process is manual for the moment. There are different alternatives available for backups:
- Establish a secure connection to a computer or phone that's in physical proximity using Nearby Sharing. This is the most secure method available.
- Connect to a server directly from Tella and choose the files you want to send to it. You can read more about the servers available here.
- Select files from your vault and export those to your phone using the Save to device button.
All exports outside of Tella's encrypted vault (to a connected server or to your phone) will be unencrypted. The only method of sharing files that transfer files directly to another encrypted vault is Nearby Sharing.
Security & Privacy
I can't remember my lock. How can I get into Tella?
Unfortunately there is no way of getting into Tella if you forgot your lock. You will have to uninstall Tella and reinstall it. There is no way of retrieving the files that were stored in Tella.
Learn more about Tella Locks in our video tutorials.
How do I migrate Tella to a new phone?
You can use Nearby Sharing to move your files to a new phone. You will need to install Tella in your new phone, establish a secure connection to it using Nearby Sharing, select all your files, and transfer those to your new phone. This feature will work, too, for Android to iOS, or iOS to Android migrations.
If you have multiple files, the full transfer might take some time. We recommend you to make sure that Tella does not lock while the transfer is in progress.
We recommend you double check that all the files has been successfully transferred before deleting those in your old phone.
Using Apple's Migration Assistant will not work: your files will be moved to the new phone encrypted, but not your encryption keys. As a result, you will not be able to decrypt and open these files.
How secure is Tella?
There is no such thing as an app that is 100% "secure". Security is dependent on the threats and risks faced by each user. With this in mind, we built Tella to protect users from device searches (at checkpoints, borders, in the street, etc) and to protect sensitive files and data, both on the device and when they send them.
To do this, Tella encrypts all data in the user's device, locks using password protections, and can be hidden with a variety of camouflage options. It also encrypts all data that is sent to servers. You can read details about how do we do this, and some risks and limitations on the Security & privacy section of Tella's.
Has Tella undergone security audits?
Yes! You can see all our security audits here.
Deploying Tella
What does it mean to "deploy" Tella?
Deploying Tella means getting Tella ready to use for your specific context and among your community or organization. This might include:
- assessing where your data will live (for example using a third party server or self-hosting it)
- deciding how are you going to structure your data
- installing and configuring the server
- training users and helping them get the app installed and configured
- planning for maintenance of the server
Please go to the For Organizations section to read more about deploying Tella.
Can you help me deploy Tella?
Yes, we'd love to! Tell us about what you want to use Tella for and in what context you want to deploy it contact us and we'll get in touch.
How is Tella different from other documentation apps?
We want to help you understand if Tella is the best app for your specific context. There are other documentation apps developed by other organizations and human rights defenders that you might consider as well.
We created this comparison table to help you understand the difference between Tella and other apps available, but of course, we may be biased 😊. For comparisons by independent organizations, have a look at the links below.
| Tella | ODK Collect KoboCollect | EyeWitness to Atrocities | CameraV | ProofMode | |
|---|---|---|---|---|---|
| On-device encryption | ✓ | ✗ | ✓ | ✓ | ✗ |
| Camouflage | ✓ | ✗ | ✓ | ✓ | ✗ |
| Usability | 😃 | 😭 | 😐 | 😐 | 😃 |
| Verifiable evidence | ✓ | ✗ | ✓ | ✓ | ✓ |
| Data-collection (data is sent to, and stored on, a remote server) | ✓ | ✓ | ✓ | ✗ | ✗ |
| Customizable forms | ✓ | ✓ | ✗ | ✗ | ✗ |
| Self-host option (full control over data) | ✓ | ✓ | ✗ | ✗ | ✗ |
| Advocacy or legal support | ✗ | ✗ | ✓ | ✗ | ✗ |
Some research and reflections about Tella--and the human rights documentation process in general--can be found here:
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Should I Use This Documentation App? by WITNESS.
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The Public International Law and Policy Group (PILPG), in partnership with The Engine Room and HURIDOCS, published a wide-ranging needs assessment report for human rights documenters, transitional justice actors, and tool developers. This microsite by The Engine Room present some of the report findings.
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The Engine Room assessed some of the tech tools available for human rights documenters here.