Directory

Open JSON-RPC standard for connecting AI applications to tools, data and prompts through servers, now stewarded under the Linux Foundation with SDKs in many languages

React framework from Vercel for full-stack web applications with file-based routing, server components, server-side rendering, static generation and API route handlers

Server-side JavaScript runtime built on the V8 engine, governed by the OpenJS Foundation, with npm as its package ecosystem

Local-first Markdown note-taking app with bidirectional links, graph view and a large community plugin ecosystem; optional paid Sync and Publish

Open-source runtime and model manager for running open-weight LLMs locally on macOS, Windows and Linux, with a REST API, OpenAI- and Anthropic-compatible endpoints and optional cloud models

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

Universal document converter that translates between Markdown, LaTeX, HTML, DOCX, EPUB, Typst, Jupyter and dozens of other formats, with citeproc and Lua filters

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

Production process manager for Node.js and other long-running programs with cluster mode, log handling, restart policies and boot-time startup scripts

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

Open-source object-relational database server with a large extension ecosystem (PostGIS, pgvector, TimescaleDB) and broad SQL coverage

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

Node.js library from the Chrome team for controlling Chrome and Firefox over the DevTools Protocol or WebDriver BiDi, used for scraping, screenshots, PDFs and testing

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

Open-source vector search engine written in Rust with filterable HNSW indexes, sparse and multi-vector support, REST/gRPC APIs and a managed cloud

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

Component-based JavaScript library for building user interfaces, created at Meta, with hooks, a declarative rendering model and server components

Encrypted, deduplicating backup program written in Go that stores snapshots in local, SFTP, S3-compatible and many cloud backends

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

Public-domain embedded SQL database engine that stores a whole database in one file and ships inside most operating systems and browsers