helios. for developers

contribute to developing, deploying and maintaining the software backbone of the new generation of Social Media services

helios. platform allows developers to build decentralized privacy-aware next generation social media apps for Android which enable the connection between people and smart devices in a secure and easy way. The platform provides P2P communication and the establishment of connections either by subscription or ad-hoc connection methods according to the users’ context and profile, respecting each users’ privacy settings.

The platform has been built with an open-source and modular approach so developers can either use the modules and components available to build their own apps for specific purposes, or create new extension service modules to add novel features to the platform.  With this approach, helios. aims ensure the growth and maintenance of the helios. platform and to strengthen the European Social Media landscape by providing a secure, private, user-friendly and innovative alternative to social media users.

the architecture

The architecture of the open source platform is based on different layer requirements identified during the first year of the project, and is composed by the helios. Core, Extension Modules, and Applications.

  • helios. Core: Provided by the helios project (initially within the project and after the project by the community), is the heart of the system and takes care of basic connectivity, security, and social networking functions developed by helios. Core components can evolve over time, in case some extension module is considered essential and is moved as a core component in the platform.
  • helios. Extension Modules: Can be developed by third-party developers to offer additional features on top of helios. core components. The helios project/community can also provide more privileged extension modules that are signed with the same key as the helios. core in order to provide the user trusted extension modules.

what's available now?

This is the CANDIDATE release of the platform, meaning that all components that have been developed within the project are publicly available for external developers and communities to build their own Android-based decentralised social media apps on top!

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Check below the documentation and GitHub page of the HELIOS Core Components and Extension Modules:

core components

User account creation and their associated keys for signing and verification of electronic signature for encryption and decryption.

Data access and layer abstraction for individual personal data storage the user might use such as smartphone, cloud, etc.

Essential messaging functionalities, discovery of other peers and basic media functionalities.

Storing of information about the social relations between the users. It supports the definition of contexts, as well as users and relations among them.

Overall context framework and API for the platform with context type implementations and detection for different sources and sensor APIs.

All the user’s data in the personal data storage shall be encrypted. It includes the functionalities for key and encryption manager to provide security and privacy settings.


The Trust Manager is a multithreaded module that periodically computes a new trust value for each node in each active context, and then updates the Contextual Ego Network with the newly computed trust value by storing it onto the corresponding edge.

extension modules

Based on the daily activity of users, the system determines the amount of HELIOS tokens for each user to gamify the experience on social media apps and reward the user for its contribution and activity to the entire community such as adding content, joining networks or checking-in on a specific location.

Advanced graph mining techniques on the users’ local social graph for interaction recommendation operations on helios. apps.

A set of algorithms for establishing trust relations and quality of the content generated and shared, based on the emotional response of users. Includes sentiment analysis, voice analysis, image and facial recognition.

Media content is distributed between the peers but using an approach similar to Torrent: peers become content sources to optimise the distribution.

Media content is made available for the complete network (as http streaming).

This functionality provides a polyvalent video player built with ExoPlayer.

Thanks to the TUS server, a user can upload content from the mobile phone to the personal storage. The upload can be paused and resumed if needed. 

Videoconf between peers, in principle, based on webRTC and using a signalling server.

This module provides semantic analysis of the HELIOS users image collections. This analysis facilitates the creation of content-aware user profiles that are either related to the concept of interests or stem from a more abstract, machine-generated user representation space.

The Social Community Detection (SCD) module is an Extension module, and is part of the Graph Mining suite provided by Task 4.3. SCD computes and updates social communities of the ego, based on the multilayer structure provided by the Contextual Ego Network (CEN), and the current status (Online/Offline) of the alters.

helios service apps

In charge of the P2P streaming and media distribution functionalities with specific components for live streaming services, video call, video on demand distribution (VoD), file transfer for multimedia content, video player, and support for multiple connected users for guaranteeing quality of experience. The module can be connected with the rewarding system between peers to enable monetization options for any type of user.

This application includes a graphical interface and involves the use of the APIs provided by the core managers, such as Profiling, Security, Context, Contextual Ego Network and Messaging. TestClient has been a key piece to validate the beta approach, i.e., a HApp (or APK) that imports AAR libraries (HELIOS components) from the Nexus repository.

tutorials