# Open Source

Open-source auth infrastructure for modern apps

Logto is an open-source authentication and authorization platform built on OIDC and OAuth 2.1, serving as an alternative to Auth0, Cognito, and Firebase Auth. It provides pre-built sign-in flows with customizable UI, social login, Google One Tap, MFA, enterprise SSO via SAML, and role-based access control. SDKs cover 30+ frameworks including React, Next.js, Vue, Flutter, Go, and Python, with multi-tenancy support for SaaS applications.

Open-source visual regression testing tool

Lost Pixel is an open-source visual regression testing tool that serves as an alternative to Percy and Chromatic. It captures and compares screenshots of UI components and application pages across Storybook, Ladle, Histoire, and custom screenshot sources like Cypress or Playwright. Integrated directly into GitHub Actions pipelines, it detects unintended visual changes before they reach production, with a free SaaS tier available for open-source projects.

Lightweight session management for TypeScript

Lucia is a lightweight open-source auth library for TypeScript providing session management primitives without abstracting the database layer. Gives developers core building blocks — session creation, validation, invalidation — while they own the schema and auth logic. Supports any database through a simple adapter. Works with Next.js, SvelteKit, Astro, Express, and Hono. For developers wanting full control over auth implementation with minimal overhead and zero vendor lock-in.

macOS and Linux VM runtime for AI agents on Apple Silicon

Lume is an open-source CLI for creating and managing macOS and Linux virtual machines on Apple Silicon, built specifically for AI agent sandboxing, CI/CD pipelines, and desktop automation. Using Apple's native Virtualization.Framework for near-native performance, it provides the missing isolation layer for running coding agents safely — so an accidental destructive command doesn't affect your host machine.

Fast async link checker written in Rust

Lychee is a fast, asynchronous link checker written in Rust that finds broken URLs and email addresses in Markdown, HTML, reStructuredText, and websites. Available as a CLI tool, Rust library, and GitHub Action, it validates links with configurable concurrency, rate limiting, and retry logic. Supports GitHub token authentication for API rate limit avoidance and can check both internal file links and external HTTP endpoints across entire repositories or websites.

Community self-hosted MCP server for Jira and Confluence (Python)

MCP Atlassian is a community-built, self-hosted Python MCP server (sooperset/mcp-atlassian) that connects AI coding agents to Jira and Confluence using API tokens or personal access tokens. It runs on your own infrastructure and supports both Cloud and Server/Data Center deployments — a flexible alternative to Atlassian's official remote MCP server when you need on-prem control, custom auth, or self-managed configuration.

IBM-backed ContextForge gateway for federating MCP, A2A, REST, and gRPC APIs

MCP Context Forge is IBM’s Apache-2.0 ContextForge project for operating a gateway, registry, and proxy across MCP servers, A2A agents, REST APIs, and gRPC services. It centralizes discovery, authentication, policy controls, federation, and observability, with deployment paths through PyPI, Docker, and Kubernetes.

Anthropic's open standard for connecting AI models to tools and data

Model Context Protocol (MCP) is Anthropic's open standard that defines how AI models communicate with external tools, resources, and data sources. Provides a universal client-server architecture for connecting LLMs to any API or service through standardized tool definitions, resource access, and prompt templates. Rapidly adopted across the AI industry as the interoperability standard for AI tool integration.

Community MCP server registry

Community-curated directory of Model Context Protocol (MCP) servers that extend AI assistants like Claude with real-world capabilities — file access, database queries, API integrations, browser control, and more. Lists servers organized by category (developer tools, data, productivity) with installation instructions and compatibility info. Helps developers discover and connect MCP servers to their AI workflows. Essential resource for the growing MCP ecosystem.

Open-source MCP server for database access

MCP Toolbox for Databases is an open-source MCP server by Google that connects AI agents to databases through a managed control plane. It handles connection pooling, authentication, and tool distribution, letting developers integrate database tools in under 10 lines of code. Supports PostgreSQL, MySQL, BigQuery, AlloyDB, Snowflake, MongoDB, Redis, ClickHouse, Neo4j, and more with ready-to-use toolsets for Claude Code, Gemini CLI, and other MCP clients.

Official TypeScript SDK for building MCP servers

The official TypeScript SDK for the Model Context Protocol, providing everything needed to build MCP servers and clients. Supports stdio, SSE, and Streamable HTTP transports with built-in auth helpers. Works across Node.js, Bun, and Deno runtimes for maximum deployment flexibility.

Open-source MCP bridge between AI assistants and the Unity Editor

MCP for Unity is CoplayDev’s MIT-licensed bridge between MCP-compatible AI assistants and the Unity Editor. It exposes tools for assets, scenes, GameObjects, scripts, tests, profiling, and build-oriented workflows. The community project supports Unity 2021.3 LTS through 6.x and is explicitly not affiliated with Unity Technologies.

Test and debug MCP servers before they ship

Open-source platform for inspecting, debugging and regression-testing MCP servers, MCP Apps and ChatGPT apps, with OAuth and protocol conformance for local and CI workflows.

Self-hosted MCP gateway for managing multiple servers behind a single endpoint

MCPJungle is a self-hosted gateway that aggregates multiple MCP servers behind a single endpoint. It provides server discovery, health checking, access control, and request routing so AI clients connect to one gateway rather than managing individual server connections. Supports server grouping, authentication, and monitoring dashboards for production MCP deployments.

CLI package manager for MCP servers with profile-based configuration

MCPM is a command-line package manager for MCP servers that handles installation, configuration, and profile management. It supports profile-based server grouping where different AI workflows use different sets of MCP servers. Features a server registry, automatic dependency resolution, and configuration file management for Claude Desktop and other MCP clients.

MCP server manager for installing and running Model Context Protocol servers

MCPorter is a management tool for discovering, installing, and running MCP servers. It provides a registry of available servers, handles dependency installation, manages configuration, and starts servers with proper environment setup. Simplifies the process of connecting AI agents to external tools through MCP by abstracting server lifecycle management. Over 5,700 GitHub stars.

Markdown with JSX components

MDX is a format that seamlessly combines Markdown with JSX, allowing authors to embed React components directly inside Markdown documents. It solves the problem of static content being too limited for modern web applications by making documentation interactive — charts, custom widgets, and live code examples can live alongside prose. MDX is the backbone of Docusaurus, Nextra, and countless React-based docs stacks.

AI-first security scanner for LLM, agent, MCP, and RAG codebases

MEDUSA is an AGPL-3.0 AI-first security scanner from Pantheon Security that checks AI and machine-learning applications, LLM agents, MCP workflows, RAG pipelines, repository-poisoning risks, secrets, and agent-specific compromise patterns.

Run LLMs natively on any device with ML compilation

MLC LLM is an open-source engine for deploying large language models natively across diverse platforms using machine learning compilation. It runs models on NVIDIA/AMD GPUs, Apple Silicon, mobile devices, and browsers via WebGPU without cloud dependencies. Features include OpenAI-compatible API, quantization support, and optimized backends for CUDA, Metal, Vulkan, and WebAssembly.

Run and fine-tune Vision Language Models locally on Mac

Open-source Python package for running and fine-tuning Vision Language Models locally on Mac using Apple's MLX framework. Supports multimodal inference with images, audio, and video across Qwen, DeepSeek, Phi, and Gemma architectures. Features OpenAI-compatible API server, Gradio chat UI, and KV cache optimization. 3.8K+ GitHub stars.

Lightweight mobile and edge AI inference engine

MNN is a lightweight, high-performance deep learning inference engine developed by Alibaba and battle-tested across 30+ Alibaba apps including Taobao, DingTalk, and Youku. It supports TensorFlow, ONNX, PyTorch, and Caffe models with optimized backends for CPU, GPU, and NPU on mobile and edge devices. MNN includes on-device LLM inference, an OpenCV-like image processing library, and Python bindings for rapid prototyping. Apache 2.0 licensed with 15K+ stars.

API mocking for browser and Node.js

Mock Service Worker intercepts network requests at the service worker level, enabling seamless API mocking for tests and development without changing application code. With 16k+ GitHub stars, MSW is the go-to solution for frontend developers who need realistic API simulation during development and testing without spinning up backend servers.

Modern data pipeline orchestration with built-in AI

Mage AI is an open-source data pipeline orchestration tool positioned as a modern alternative to Apache Airflow. It provides a visual pipeline editor, native AI integrations for generating pipeline code, real-time streaming support, and built-in data quality checks. Mage handles batch and streaming workloads with a developer-friendly notebook-style interface and deploys to any cloud provider.

Human-in-the-loop web agent you can co-pilot in real time

Magentic-UI is a Microsoft Research web agent with a human-in-the-loop interface for browsing, coding, and file tasks. It plans multi-step actions, asks for approval before executing, and lets users co-pilot by taking over the browser mid-task. Built on AutoGen, it runs a team of specialized agents for web browsing, file handling, and code execution with full action transparency and safety guardrails.

MCP server for AI-powered UI component generation

Magic MCP is an MCP server from 21st.dev that enables AI agents to generate polished UI components inspired by modern design engineering patterns. It gives coding agents access to a library of high-quality component templates and design patterns, accelerating frontend development through intelligent component scaffolding.

Collection of 150+ animated React components for landing pages

Magic UI provides over 150 animated React components designed for creating visually impressive landing pages and marketing sites. Components include animated text effects, particle backgrounds, scroll-triggered animations, 3D cards, and interactive elements built on Tailwind CSS and Framer Motion. Copy-paste installation model following the shadcn/ui pattern.

AI-powered file-type detection at Google scale

Open-source AI-powered file-type detection tool from Google that uses a custom deep-learning model under a few megabytes to identify more than 200 binary and textual content types in milliseconds, even on a single CPU. Magika ships as a CLI, Python package, JavaScript/TypeScript library, and an ONNX model, achieves around 99% accuracy on its test set, and is already used at Google scale across Gmail, Drive, and Safe Browsing as well as by VirusTotal and abuse.ch.

Smart LLM router that cuts inference costs up to 70%

Manifest is an open-source smart model router that intelligently routes LLM requests to the cheapest capable model, reducing inference costs by up to 70% without sacrificing output quality. It uses a 23-dimension scoring algorithm to evaluate 300+ models across providers including OpenAI, Anthropic, Google, and DeepSeek, with automatic fallbacks and budget controls. Manifest can be deployed as a cloud service, local plugin, or self-hosted Docker container with transparent routing logic.

Convert any file to Markdown for LLM pipelines

MarkItDown is a lightweight Python utility by Microsoft that converts files into clean Markdown optimized for LLM pipelines and text analysis. It supports PDF, Word, Excel, PowerPoint, HTML, images with OCR, audio with transcription, and text formats like CSV, JSON, and XML. The tool preserves document structure including headings, tables, lists, and links while keeping output token-efficient. It offers a CLI, a four-line Python API, Docker support, and a plugin architecture for extensions.

No-code AI web scraping platform with visual workflow builder

Maxun is a no-code web scraping platform that uses AI to extract structured data from websites through a visual workflow builder. Users point and click on the data they want to extract, and Maxun generates resilient scraping workflows that handle pagination, authentication, and dynamic content. Features anti-bot detection avoidance, scheduled runs, and API access for integration. Over 15,300 GitHub stars.

On-device ML solutions for mobile and edge AI

MediaPipe is Google's open-source framework for building on-device machine learning pipelines across mobile, web, desktop, and edge platforms. It provides pre-built solutions for face detection, hand tracking, pose estimation, object detection, image classification, text classification, and on-device LLM inference. MediaPipe runs entirely locally without cloud dependencies, supporting Android, iOS, Python, and web browsers.

Lightning-fast, open-source search engine — a developer-friendly Algolia alternative.

Meilisearch is an open-source, lightning-fast search engine written in Rust. Designed as a developer-friendly alternative to Algolia with typo tolerance, faceted search, filtering, and sorting out of the box. Sub-50ms response times. Easy to deploy and configure with a RESTful API.

Declarative code-first ELT data integration

Meltano is a declarative, code-first data integration engine with 500+ Singer connectors for building ELT pipelines. It replaces custom API integration code with configuration-driven pipeline definitions that live in version control alongside application code. Integrates with dbt for transformation, supports scheduling and monitoring through a unified CLI, and powers production pipelines at scale.

SQL-native memory infrastructure for AI agents and applications

Memori is an AI memory engine that provides persistent, queryable memory for agents and applications using SQL-native storage. It stores structured memories with semantic search, temporal awareness, and relationship tracking, enabling AI systems to remember user preferences, past interactions, and contextual facts across sessions. With 12,900 GitHub stars, it offers a database-native approach to the agent memory problem.

Multi-agent framework simulating a software company

MetaGPT is an open-source multi-agent framework with 56K+ GitHub stars that simulates a software company by assigning roles — product manager, architect, engineer, QA — to AI agents collaborating through structured SOPs. Given a one-line requirement, it outputs user stories, competitive analysis, data structures, APIs, and working code. Features incremental development, human feedback integration, and experience-based learning for continuous improvement across iterations.

Connect AI agents to hundreds of integrations via one interface

Metorial is an open-source integration hub that connects AI agents to hundreds of third-party services through a single interface with built-in OAuth handling, scaling, and monitoring. It simplifies the complexity of managing multiple MCP connections by providing a unified connector layer for agentic workflows.

Unified Python/.NET framework for multi-agent AI

Microsoft Agent Framework is Microsoft's official unified SDK for building multi-agent AI workflows in Python and .NET. It consolidates Semantic Kernel and AutoGen into a single framework with MCP tool integration, graph-based workflows, human-in-the-loop patterns, and multi-agent orchestration. The framework reached Release Candidate status in February 2026 and is Microsoft's recommended path for production agent development.

High-performance S3-compatible object storage

MinIO is a high-performance, S3-compatible object storage server designed for AI, machine learning, and data-intensive workloads. Written in Go, it delivers industry-leading throughput for both read and write operations while maintaining full compatibility with the Amazon S3 API. MinIO includes an embedded web console for bucket management, a command-line client, and supports erasure coding, bitrot protection, and encryption at rest for enterprise-grade data durability.

MCP server for MiniMax speech, video, and image APIs

Official MiniMax Model Context Protocol server enabling AI applications and code editors to access text-to-speech, voice cloning, image generation, video generation, and music creation APIs. Designed for Claude Desktop, Cursor, and Windsurf integration with stdio and SSE transport support, regional API endpoints for global and China regions, and flexible resource handling for seamless generative AI workflows.

Free MIT-licensed drop-in replacement for LocalStack

MiniStack is a free, MIT-licensed drop-in replacement for LocalStack that emulates 33 AWS services using real infrastructure — actual Postgres for RDS, real Redis for ElastiCache, real Docker for ECS — rather than faking API responses. Born from LocalStack's surprise paywall in March 2026, it starts in 2 seconds, idles at 30MB RAM versus LocalStack's ~500MB, and runs real services for accurate local AWS development.

Multi-provider AI code completion as-you-type for Neovim

Neovim plugin that streams inline code completions from your choice of LLM (OpenAI, Claude, Gemini, Codestral, Ollama, Llama.cpp, and more), with no proprietary background binary.

Write components once and compile them into native code for multiple frameworks

Mitosis is Builder.io-backed open-source infrastructure for writing a component once and compiling it into native framework components for React, Vue, Angular, Svelte, Qwik, Solid, React Native, and other targets. It supports cross-framework design systems and Figma-to-code synchronization, but is distinct from the Builder.io visual builder product.

Project documentation with Markdown

Python-based static site generator purpose-built for project documentation. Simple YAML configuration, fast build times, and a rich plugin ecosystem. The Material for MkDocs theme adds a polished look with search, dark mode, and advanced navigation features. The go-to documentation tool for open-source projects and internal engineering docs that need to look professional with minimal effort.

MCP server for mobile device automation and testing

Mobile MCP is an open-source MCP server that enables AI agents to automate Android and iOS devices — navigating apps, tapping elements, extracting screen content, and running tests on simulators, emulators, and physical devices. It brings agentic mobile engineering to any MCP-compatible AI assistant.

Flexible JavaScript test framework

Feature-rich JavaScript test framework for Node.js with BDD/TDD interfaces, flexible assertion library choice, and extensive plugin support. The veteran test runner trusted by thousands of projects, offering async test support, configurable reporters, and a mature ecosystem that makes it reliable for both unit and integration testing in Node.js applications.

Disaggregated KV cache storage and transfer for LLM serving

Open-source infrastructure for disaggregated LLM serving that pools KV caches across prefill and decode workers, with high-performance transfer, distributed storage and integrations for vLLM and SGLang.

YC-backed multimodal RAG platform for documents, images, and video

Morphik is a YC-backed multimodal RAG platform that ingests and retrieves information from documents, images, tables, and video content. It processes complex document layouts including charts, diagrams, and multi-column formats that traditional text-only RAG systems handle poorly. Provides API-first integration for building knowledge bases that understand visual as well as textual information.

Production-ready React animation library, evolved from Framer Motion

Motion (formerly Framer Motion) is the most popular React animation library, providing a declarative API for complex animations, gestures, layout transitions, and scroll-triggered effects. Supports spring physics, keyframes, shared layout animations, and exit animations. Powers animations across thousands of production React applications with an API designed for developer ergonomics.