jq vs Polars

jq is a free command-line processor for selecting and transforming JSON data. A jq filter takes an input and produces output; filters can be combined to access nested attributes, construct objects, gather results into arrays, or make other transformations. It reads whitespace-separated JSON values and writes serialized results separated by whitespace. Each expression runs on each input value and may produce zero or more outputs. For very large inputs, the --stream option parses incrementally. Output options include compact, raw, ASCII, sorted-key, and colored forms. Written in portable C, jq has no runtime dependencies, and a standalone binary can be copied to another machine of the same type. Standalone executables are available for Linux, macOS, and Windows, with packages listed for Linux distributions and package managers including Homebrew, MacPorts, winget, Scoop, and Chocolatey. A Docker image is also available. Release binaries have SHA-256 checksums, and signed release artifacts use jq release keys. The code is licensed under MIT; the documentation uses CC-BY-3.0.

Polars is an open-source DataFrame library for data manipulation, designed for single-machine processing with a typed, expressive API. Its multithreaded query engine is written in Rust and uses vectorized columnar processing to execute work in parallel. A query optimizer selects an execution plan, and the streaming API can process datasets larger than memory without holding all results in memory. Installation examples cover Python, Rust, and JavaScript. Supported formats include CSV, JSON, Parquet, Delta Lake, Avro, Excel, Feather, and Arrow IPC; the homepage also lists databases and cloud storage. Polars can read and write data in AWS S3, Azure Blob Storage, and Google Cloud Storage. The open-source library costs nothing under the MIT license. Polars Cloud runs distributed queries through the Polars API and scales work from local execution to a cluster; it is available on AWS. Its 30-day trial begins when an organization connects its first workspace to AWS, and its compute runs in the customer's cloud environment. Polars On-Prem supports Kubernetes and bare-metal deployments, including air-gapped Enterprise deployments.