APEx (Algorithm Propagation Environment(s)) is a comprehensive suite of services tailored to support ESA projects by sustaining, enhancing, and propagating Earth Observation (EO) project results and algorithms. It ensures the longevity, accessibility, and efficient execution of EO algorithms within the larger EO community.

The Algorithm Hosting Service ensures that your project’s algorithms remain accessible and functional within the EO community beyond the project's completion. It includes an algorithm catalogue for easy browsing and execution, automated testing and benchmarking to maintain algorithm integrity, and support for APEx compliance. It also helps integrate algorithms into ESA’s Network of Resources (NoR), enhancing visibility and potential revenue generation.

APEx manages the execution of algorithms by leveraging the capabilities of existing environments that are onboarded on the NoR and APEx compliant, compatible with openEO and Application Package standards. These environments address key concerns such as data availability, operational stability, parallelization, and cloud resource management, ensuring efficient and reliable algorithm execution.
 

APEx provides guidelines and support for ensuring that algorithms onboarded to the platform are APEx compliant. This includes adhering to interoperability standards, linking algorithms to execution tools, and providing clear integration instructions. Projects can request additional support from APEx to navigate this process effectively.

The Upscaling Service simplifies the preparation and execution of large-scale EO data processing tasks, which can take days or weeks to complete. It offers tools to manage and monitor these tasks, including progress monitoring and cost estimation. The service aims to lower the burden of generating large-scale maps and ensures compliance with upscaling environments.

Yes, APEx services are designed to accommodate both onboarded and private algorithms. If your algorithm is not onboarded to APEx, you can still participate in services like Algorithm Enhancement or Algorithm Intercomparison by running your algorithm in an APEx interactive development environment.

To request a service from APEx, please navigate to the dedicated services page, where you will find detailed instructions on how to contact the APEx team. Once you’ve made contact, your request will be evaluated by ESA. If approved, you will be granted access to the requested service. 

As of mid-2026, the project aims to onboard all of its services onto ESA’s Network of Resources (NoR). This transition will enable projects to easily request access to one or more APEx services directly through the NoR platform. 

Integrating your algorithm into ESA’s Network of Resources (NoR) enhances its visibility within the EO community and opens up opportunities for generating additional revenue streams. NoR integration ensures that your algorithm is accessible as a reusable, on-demand process, promoting its long-term utility and impact.

The Stakeholder Engagement Facility (SEF) collaborates closely with the APEx team to provide outreach and training to maximise the uptake of onboarded algorithms. It ensures that project results reach a broader audience and that users are well-supported in integrating these algorithms into their workflows.