Directory

Foundational Python library for n-dimensional arrays, vectorized math, linear algebra, random numbers and the array API used by the scientific stack

Modular open-source business suite (CRM, invoicing, accounting, inventory, website, HR) with an LGPL community edition and a hosted or licensed enterprise edition

Lightweight open-source Python and TypeScript framework for agents, handoffs, guardrails, sessions and tracing, defaulting to OpenAI's Responses API with adapters for other providers

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

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

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

Algorithmic trading platform built on the open-source LEAN engine, with cloud backtesting, research notebooks and brokerage-connected live trading

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