Polars is an open-source DataFrame library for Python and Rust that processes tabular data in parallel, using a columnar, vectorised engine built on Apache Arrow. It reads and writes formats such as CSV, Parquet, JSON and Delta Lake, and offers a streaming API for data sets larger than memory. The library is released under the MIT licence. Polars Cloud is a managed service that runs Polars queries in the cloud or on-premise.
Polars B.V. is registered in Amsterdam, as the Polars Cloud terms state, so the company is established in the EU. The library runs locally on users' machines, so the data it processes stays under the organisation's control. For Polars Cloud, the terms describe customer data as held in the customer's own AWS environment. They reference the GDPR, with Polars acting as an independent controller for limited personal data such as account information. Before using the cloud service, organisations should still confirm the hosting region and the processing terms.