Directory

The standard Python DataFrame library for labeled tabular data, time series and I/O to CSV, Excel, SQL, Parquet and more

Lightweight Python library for declaring and validating DataFrame schemas for pandas, Polars, PySpark and other backends, with type-hint style models

Microsoft's browser automation and end-to-end testing framework driving Chromium, Firefox and WebKit from one API in TypeScript, Python, Java and .NET

MIT-licensed interactive charting libraries for Python (plotly.py), JavaScript (plotly.js) and R, plus the Dash framework for analytical web apps

Rust-based DataFrame library with Python, Rust, Node and R bindings offering lazy query optimization, multithreading and Arrow-native memory

Python workflow orchestration library and server where decorated functions become observable, retryable flows, with Prefect Cloud as hosted option

Open-source computational notebook ecosystem: the .ipynb format, kernels for Python, R and Julia, JupyterLab and Notebook interfaces and JupyterHub

Python data-validation library using type hints to parse, validate and serialize models, with a Rust core; the schema layer behind FastAPI and many LLM SDKs

Type-safe Python agent framework from the Pydantic team with validated structured outputs, dependency injection, swappable model providers, MCP, durable execution and evals

Python library for portfolio optimization: efficient frontier, Black-Litterman, hierarchical risk parity and discrete allocation

Python testing framework with plain assert statements, fixtures, parametrization and a large plugin ecosystem, the de facto standard for Python test suites

General-purpose, dynamically typed programming language with a large standard library and the dominant ecosystem for data science and machine learning

Open-source deep-learning framework with eager tensors, autograd, torch.compile and distributed training, governed by the PyTorch Foundation and the base of most LLM tooling

Open-source desktop GIS for viewing, editing, analysing and publishing vector and raster geodata, extensible with Python plugins

Open-source C++ library for quantitative finance covering instruments, term structures, pricing engines and calendars, with Python and other bindings

Open-source scientific publishing system from Posit that renders Markdown with executable Python, R, Julia or Observable code to HTML, PDF, Word, slides, websites and books via Pandoc

Open-source Python library for evaluating LLM and RAG applications with LLM-driven and custom metrics, experiments, dataset management and result tracking

Open-source Python framework for distributing tasks, actors and ML workloads across a cluster, with libraries for data processing, training, tuning, serving and reinforcement learning

Python library for quantitative portfolio optimization with many risk measures, robust estimators and hierarchical clustering models

BSD-licensed Python machine-learning library for classification, regression, clustering, dimensionality reduction, preprocessing and model selection on NumPy and SciPy

Core open-source Python library for scientific computing on NumPy arrays: optimization, integration, interpolation, linear algebra, sparse matrices, statistics, signal processing

Mature open-source Python framework for writing crawlers (spiders) that fetch pages asynchronously, extract structured items and export them through pipelines

Python library for computing and training embedding, cross-encoder reranker, sparse and multi-vector retrieval models, maintained by Hugging Face with thousands of pretrained models on the Hub

Python documentation generator using reStructuredText or MyST Markdown with cross-referencing, API autodoc and output to HTML, PDF via LaTeX, ePub and man pages