Directory

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

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

Posit's multi-language data-science IDE built on Code OSS, with first-class R and Python consoles, variables and plots panes, under the Elastic License 2.0

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

Python IDE from JetBrains with deep static analysis, refactoring, debugging, scientific tooling and a unified free core with a paid Pro tier

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

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

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

Web scraping API with anti-bot bypass, JavaScript rendering, cloud browsers, screenshots, AI extraction and a crawler, billed in credits per request

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

API that returns live search-engine result pages from Google and other engines as structured JSON, with localization, device and search-type parameters

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

Pure-Python computer algebra system for symbolic algebra, calculus, equation solving, matrices, physics modules, code generation and LaTeX output

Cloud platform for open-source models: serverless and dedicated inference, fine-tuning, GPU clusters, batch jobs and code sandboxes behind an OpenAI-compatible API

Hugging Face's model-definition library for text, vision, audio, video and multimodal models, with Pipeline, Trainer and generate APIs used as the reference by training and inference engines

Open-source framework for fine-tuning and running LLMs with reduced memory, covering LoRA, QLoRA, full fine-tuning and RL, GGUF export, Dynamic quantizations and a local Studio/Desktop UI

Python library for vectorized backtesting and portfolio analysis built on pandas, NumPy and Numba, with a commercial PRO edition

Declarative Python visualization library that compiles concise chart specifications to Vega-Lite JSON for interactive, grammar-of-graphics plots