Stellio is composed of 3 business services:

  • Entity service is in charge of managing the information context, it is backed by a neo4j database
  • Search service is in charge of handling the temporal (and geospatial) queries, it is backed by a TimescaleDB database
  • Subscription service is in charge of managing subscriptions and subsequent notifications, it is backed by a TimescaleDB database

It is completed with:

  • An API Gateway module that dispatches requests to downstream services
  • A Kafka streaming engine that decouples communication inside the broker (and allows plugging other services seamlessly)

The services are based on the Spring Boot framework, developed in Kotlin, and built with Gradle.

Quick start

A quick way to start using Stellio is to use the provided docker-compose.yml file in the root directory (feel free to change the default passwords defined in the .env file):

docker-compose up -d && docker-compose logs -f

It will start all the services composing the Stellio context broker platform and expose them on the following ports:

  • API Gateway: 8080
  • Entity service: 8082
  • Search service: 8083
  • Subscription service: 8084

Please note that the environment and scripts are validated on Ubuntu 19.10+ and MacOS. Some errors may occur on other platforms.

Docker images are available on Docker Hub.


Developing on a service


  • Java 11 (we recommend using sdkman! to install and manage versions of the JDK)

To develop on a specific service, you can use the provided docker-compose.yml file inside each service's directory, for instance:

cd entity-service docker-compose up -d && docker-compose logs -f

Then, from the root directory, launch the service:

./gradlew entity-service:bootRun

Running the tests

Each service has a suite of unit and integration tests. You can run them without manually launching any external component, thanks to Spring Boot embedded test support and to the great TestContainers library.

For instance, you can launch the test suite for entity service with the following command:

./gradlew entity-service:test

Building the project

To build all the services, you can just launch:

./gradlew build

It will compile the source code, check the code formatting (thanks to ktLint) and run the test suite for all the services.

For each service, a self executable jar is produced in the build/libs directory of the service.

If you want to build only one of the services, you can launch:

./gradlew entity-service:build

Working locally with Docker images

To work locally with a Docker image of a service without publishing it to Docker Hub, you can follow the below instructions:

  • Build a tar image:
./gradlew entity-service:jibBuildTar
  • Load the tar image into Docker:
docker load --input entity-service/build/jib-image.tar
  • Run the image:
docker run stellio/stellio-entity-service:latest


To start using Stellio, you can follow the API quick guide published in our NGSI-LD API & Data Model repository.

As the development environment does not make use of the authentication setup, you can ignore related information in the API quick guide.