API Info


Welcome to the OpenET Application Programming Interface (API)! The API supports machine to machine data retrieval to enable automated and operational use of the data within a broad array of applications.

Current OpenET Account Holders will need to create a new account here to be able to access the Data Explorer on www.openetdata.org and/or the new API (whether you are signing up for API access or not). The API documentation and interface can be accessed here. The API Terms of Service can be accessed here.

Access to the Data Explorer and the API  will continue to be free, though subject to user quotas to balance usage of compute resources across all OpenET users.

How Do I Use the API?

Whether you’re a seasoned developer or just starting out, our user-friendly API documentation will guide you through the various endpoints, parameters, and response formats, enabling you to tailor queries to the API to suit your specific needs. Training videos are available here:

Training Videos

Training videos are also available on the OpenET YouTube channel. If you have questions or need help using the API, please feel free to reach out to us at support@openetdata.org.

Why an API?

The API was developed so that data from OpenET can be easily integrated into other data and decision support systems. It also supports queries of data using your own field boundaries or areas of interest, and can help generate custom reports for specific time periods of interest. The API enables automated and operational use of the data within irrigation scheduling tools, hydrologic models, water accounting or trading platforms, and other farm, ranch, and water management software. 

While data accessible through the Data Explorer Interface will be a rolling 5-6 year archive, the OpenET API will support retrieval of data over longer time periods with data availability extending for 30+ years for some geographies in the near future. The ultimate goal is to develop ET data archives from 1985 to present across the United States. 

By providing access to such a wide range of functionalities and data, our API helps foster innovation, planning and the creation of novel solutions.

How Much Free Data Can I Access with the API?



In an effort to ensure fair usage and maintain equal access for all users, OpenET has implemented user quotas to balance usage of available compute resources across all users. This measure is aimed at preventing overuse by individual users, which could potentially slow down or prevent access for all users of the platform. Additionally, by constraining free access, the OpenET nonprofit can effectively manage compute costs and continue to offer this essential service to the public. The free quota encompasses four dimensions, each designed to strike a balance between usability and responsible resource management:


1. Number of total queries per month will be limited to 100 queries per registered user.

2. Area: For each query, the total number of acres queried can not exceed 50,000 acres.

3. Geographic Complexity:

a. When querying the raster data using custom user-generated shapefiles, users will be limited to 50 polygons per query.

b. When querying OpenET’s geodatabase, users will be limited to a maximum of 100 fieldIDs per query.


4. Earth Engine Compute Units(EECUs): Users will be limited to no more than 10,000 Earth Engine Compute Unit-seconds for exports per month. These are defined by Earth Engine here, and most users should not reach this limit. This constraint is intended to serve primarily as a backstop in case of incorrectly formatted API queries.


Additional guidance on the API Quota information can be found here. Happy exploring, and again, please don’t hesitate to reach out with questions and/or use case stories at support@openetdata.org.

How Can I Retrieve Larger Volumes of OpenET Data?

For retrieval of large volumes of data, users are encouraged to retrieve OpenET data directly from the OpenET data archives in the Google Earth Public Data Catalog.

Users can also register their Google Earth Engine account and Google Cloud Project ID in their OpenET profile. Linking a user’s Google Earth Engine account and Google Cloud Project ID to their OpenET account will avoid some of the OpenET quota limits. Users are still subject to monthly request limits and may still need to break larger queries into smaller units (in terms of spatial area or time period) to avoid memory timeout errors on Earth Engine.

For stories on how others are using the OpenET API, please see:

  1. Delta ACP Use Case 
  2. Colusa Subbasin Use Case
  3. Other Use Cases