Great Expectations (GX Core) is an open-source Python library for data quality. Teams define "Expectations", which the project describes as expressive and extensible unit tests for data, and run them to validate datasets within their pipelines. The library works with orchestrators and data platforms such as Airflow, Databricks, BigQuery, Postgres and Snowflake, and can publish readable test documentation to object storage. You install GX Core with pip and it runs wherever your Python environment runs.
The software is released under the Apache 2.0 licence. The original company, Great Expectations, is US-based. In May 2026 it announced that its commercial cloud service, GX Cloud, is being acquired by the US analytics company FICO and would no longer be publicly available from 1 June, and that Fivetran, also a US company, plans to become steward of the open-source community and GX Core. Because GX Core runs in your own environment, your data is processed wherever you run the library. For a European organisation, the main point to watch is which US company steers the project's future.