Polars Genson

August 23, 2025 · View on GitHub

Fast JSON schema inference with support for Polars DataFrames.

Project Structure

This workspace contains multiple interconnected crates, most people will probably want the Python package:

Python Package

polars-genson-py/ - Python bindings and Polars plugin

Quick Start

pip install polars-genson[polars]

import polars as pl
import polars_genson

df = pl.DataFrame({
    "json_data": [
        '{"name": "Alice", "age": 30, "scores": [95, 87]}',
        '{"name": "Bob", "age": 25, "city": "NYC", "active": true}'
    ]
})

json_schema = df.genson.infer_json_schema("json_data")
polars_schema = df.genson.infer_polars_schema("json_data")

Rust Libraries

genson-core/ - Core JSON schema inference library
polars-jsonschema-bridge/ - JSON Schema ↔ Polars type conversion
genson-cli/ - Command-line schema inference tool

Features

Fast schema inference from JSON strings in Polars columns
Dual output formats: JSON Schema and native Polars schemas
Complex type support: nested objects, arrays, mixed types
Multiple JSON formats: single objects, arrays, NDJSON
Rust performance with Python convenience

Documentation

Each component has detailed documentation:

Python users: See polars-genson-py/README.md
Rust developers: See individual crate READMEs
Development: See DEVELOPMENT.md

License

Licensed under the MIT License. See LICENSE for details.