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What is the Harmonized Data Access (HDA) API?
What is the Harmonized Data Access (HDA) API?

The Harmonized Data Access (HDA) is a REST-based API developed by WEkEO, also available in a Python package, to download WEkEO data.

David Bina avatar
Written by David Bina
Updated over a week ago


WEkEO is a data platform that provides access to a wide range of Earth Observation data. This data can be found in the WEkEO catalogue, which offers a variety of datasets from different providers. In order to download this data, WEkEO offers a convenient tool called the Harmonized Data Access (HDA) API.

The HDA is a REST-based API that all users can utilize to download WEkEO data. It is free of charge, you only need a WEkEO account. Even when downloading data from the Data Viewer, calls are made behind the scene through the HDA! That's why you can see all the jobs created from the Viewer or when using the HDA programmatically, in the Jobs tab of the Data Viewer.

Moreover, WEkEO also created the hda Python package to use the HDA in a programming approach, for an easy-to-use experience in Python, but also in R.

In this article, we will briefly introduce the HDA REST API and the hda Python package. We invite you to check the listed articles to learn more in details how to use both.


The HDA API is a RESTful API that allows users to easily download data from the WEkEO platform. This API follows the REST (Representational State Transfer) architecture, which means that it uses HTTP requests to retrieve or send data. This makes it a simple and efficient way to access and download data from WEkEO.

πŸ’‘Definition of a REST API (click me)

A REST API (Representational State Transfer Application Programming Interface) is a type of web service that allows interaction with web-based systems using a set of predefined stateless operations. It is based on the principles of REST, which is an architectural style designed for networked applications, and leverages standard HTTP methods to perform CRUD (Create, Read, Update, Delete) operations.

πŸ” A detailed example on how to use of the HDA REST API can be found in this article:

HDA WEkEO Broker

The HDA WEkEO Broker is an interface explaining in details all the different routes you can call in the HDA REST API. By browsing the categories, you'll see the different available calls. Clicking on one of them will let you see all the results you can get:

To authenticate on the broker, you can retrieve your token by clicking on your WEkEO profile then on My API token:

Then, click on Authorize from the broker page, paste your token and click on Authorize:

πŸ’‘WEkEO Pro Tip: you can run a command from the WEkEO HDA Broker UI by clicking on Try it out.

The hda Python package

To make it even easier for users to access the HDA API, WEkEO has developed a Python package called hda. This package provides a set of functions that allow users to interact with the HDA API and download data from WEkEO.

The hda package is available for download and installation via pip and conda:

  • Installation of hda via pip:

    pip install hda

  • Installation of hda via conda:

    conda install conda-forge::hda

πŸ” You will find two detailed examples on how to use the hda package in Python and also in R in the following articles:

Now that you know what the HDA REST API is and how to access it using the hda Python package, you can start downloading data from WEkEO! πŸ™Œ

What's next?

We are user-driven and we implement users' suggestions, so feel free to contact us:

  • through a chat session available in the bottom right corner of the page

  • via e-mail to our support team (

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