Description Updated
Mar 17, 2023

Many organizations rely on information collection in their work, whether in the form of notes and images or structured data collected using forms. Tella provides a data collection app designed for security from the ground up, making it an excellent choice for those doing human rights abuse documentation, working in sensitive environments, or who are particularly concerned about privacy. Tella can be connected to a cloud-based server for automatic uploading of information when online.


Tella is a great choice for many organizations doing data collection, whether free-form, multimedia, or structured. While designed for the most high-risk environments, it is equally useful – and very secure – for a variety of more commonplace data or media gathering. Data must be collected through smartphones, but an always-on internet connection is not necessary as Tella will wait to upload data until a connection is possible.

Tella is a tool for data collection, particularly in repressive information environments or in places with limited internet connectivity. Tella is unique in that it was designed for human rights abuse documentation, one of the most challenging and dangerous activities organizations and activists can engage in. As such, Tella was built from a safety perspective but also works well in environments without significant risks. 

Tella can capture and securely store pictures, video, or audio directly from the app, or upload media already on your device. 

Organizations designing data collection programs can create standard structured data forms, accessible by surveyors on the Tella app, enabling consistent formats complete with data validation to help guarantee accuracy. Each individual gathering information can make as many copies of a form as needed for the number of sources they are surveying.

Tella can integrate with a cloud-hosted database to upload and aggregate information from a device - particularly important in sensitive environments where information collectors may wish to capture data before sending it off to a secure online database. For places with limited, expensive, or inconsistent internet, Tella will opportunistically connect to servers when a data connection becomes available, and so does not need the always-on internet connection that is required by alternatives such as Google Forms.


Tella is free, open source software. The apps are available for iOS and Android for free from their respective App Stores.

Technical Requirements/Capacity

Using Tella is relatively straightforward for an individual user. More sophisticated security measures, such as app hiding or data wiping require a bit more savvy and care. 

Creating a central cloud database and linking Tella apps to it for online uploading will require moderate technical ability, though only data collection managers need to do this, and it is straightforward for data enumerators to connect  once the cloud database is created.

Support Available

Tella has very limited online documentation. The staff at Horizontal have historically been very responsive to those in the rights and democracy community. 

Maintenance considerations

As with any app, Tella should be updated when new versions are available. 


Collection of sensitive information, particularly human rights abuse documentation, can be dangerous in hostile spaces. While Tella provides security tools in the app, users need to fully understand the risks they face and how to mitigate them. Particularly if a user and their phone, with the Tella app, are seized by hostile individuals, all the clever security measures in Tella may not be enough. If you are working in a high risk environment, please get professional support and engage in a holistic risk assessment.

Using a Tella cloud server requires a different set of risk analyses and introduces new forms of threats.

Case Study - Myanmar Secure Data Collection

Political crises can lead to brutal repression and human rights abuses. After the shocking military coup in Myanmar in 2021, the junta quickly moved to suppress dissent, imprisoning opposition and engaging in widespread violence. Many citizens, horrified by their country’s rapid descent into repression, wanted to document the human rights violations unfolding all around them in hopes of sparking international condemnation or eventual justice. Capturing such evidence, though, can be very dangerous for those hoping to provide future accountability. Tella, a data collection app designed for such sensitive situations, has been widely used in Myanmar for securely collecting, storing, and disseminating information on abuses of the military regime.  Horizontal, the company who created and supports Tella, comes out of the civil society activism space and understands the needs and desires of the community. NDI has worked with Tella for many years, helping support the free, open-source product by funding new features and using it in several country contexts.

Designed from the beginning with user security and privacy in mind, Tella has a wide range of capabilities to help protect you and your data which proved critical in Myanmar. The app saves media (video, pictures, or audio) in a special encrypted data store, separate from your normal photo library. Tella also has a “camouflage” mode that makes the app harder to find and a quick panic-button delete mode that erases all data and traces – all of which has come in useful for the activists when confronted by blockades and searches by regime security forces.

Large organizations can use Tella, too. By connecting the app to a cloud-hosted database, the individual forms collected by participants can be aggregated in a central place for further analysis. NDI has used Tella in this way as a part of election observation missions with hundreds of observers sending standard data forms back for central processing, enabling independent non-partisan observers to document problems and establish the integrity of the vote. Each election observer configured their app to connect to the central server, which then automatically sent the data collection forms to each user. As they filled out their reports, observers would save each form and Tella would either send immediately or, in more remote areas, wait until there was a good network connection and then submit all of them. Tella works with KoboToolbox, Uwazi, and other popular ODK-compatible databases, including Apollo

Your security considerations may not be so daunting as that faced by these human rights activists after the coup in Myanmar, but whether capturing human rights abuse documentation for future justice and accountability or simply survey results from conversations with citizens, Tella is an effective solution built by and for the civic community to take care of individual and organizational data collection needs.

Tool Category
Product Type