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

Open-source learning management system used by universities and schools for courses, assignments, quizzes, grading and forums, self-hosted or via MoodleCloud

Oracle's widely deployed open-source relational database server, offered as a GPL community edition and commercial enterprise and cloud editions

Lightweight Go messaging system with core pub/sub and request-reply plus JetStream persistence, key-value and object stores; a CNCF project

Native property-graph database queried with Cypher, offered as a GPL community edition, a commercial enterprise edition and the AuraDB cloud service

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

JavaScript data notebooks and the open-source Observable Framework static-site generator for data apps, from the maintainers of D3 and Plot

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

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

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

Vendor-neutral, machine-readable standard for describing HTTP APIs in JSON or YAML, maintained by the OpenAPI Initiative under the Linux Foundation

Apache-2.0 search and analytics suite forked from Elasticsearch and Kibana, governed by the OpenSearch Software Foundation

Collaborative online LaTeX editor with real-time co-editing, templates and reference-manager sync, available as a hosted service and an AGPL self-hosted edition

Read-only query service for OpenStreetMap data using the Overpass QL language, available on public instances or self-hosted

PostgreSQL extension adding vector types, distance operators and HNSW/IVFFlat indexes for similarity search inside the database

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

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

Spatial extension for PostgreSQL adding geometry, geography and raster types with indexing and hundreds of SQL functions

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

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

Opinionated code formatter for JavaScript, TypeScript, CSS, HTML, Markdown, YAML and more that reprints code from its syntax tree with few options

TypeScript ORM with a declarative schema language, generated type-safe client and migration tooling, from the company that also offers Prisma Postgres and related hosted services

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