Open Source Tools

Input and output security scanners for LLM applications

LLM Guard is an open-source security toolkit by Protect AI that provides 15 input scanners and 20 output scanners to protect LLM applications from prompt injection, PII leakage, toxic content, secrets exposure, and data exfiltration. Each scanner is modular and independent — pick the ones you need, configure thresholds, and chain them into a pipeline. The library works with any LLM and has been downloaded over 2.5 million times. MIT licensed, Python 3.9+.

Reusable KV cache infrastructure for scalable LLM inference

Open-source KV cache management layer that persists, offloads and reuses model key-value caches across requests and serving engines to reduce repeated prefill work and improve inference throughput.

Open-source toolkit for quantizing, deploying, and serving LLMs and vision-language models

LMDeploy is an Apache-2.0 toolkit for self-hosting LLM and vision-language model inference with TurboMind and PyTorch engines. It combines continuous batching, blocked KV cache, tensor parallelism, AWQ and KV-cache quantization with OpenAI-compatible APIs, multi-GPU distribution, offline pipelines, and production metrics.

Open-source multi-type data labeling platform

Label Studio is an open-source data labeling tool by HumanSignal supporting images, text, audio, video, and time series. It offers ML-assisted pre-labeling, customizable XML-based annotation interfaces, multi-user review workflows, and REST API access. Used for computer vision, NLP, speech, and LLM fine-tuning including RLHF annotation pipelines.

Visual framework for building multi-agent AI apps

LangFlow is an open-source visual framework for building multi-agent AI apps with drag-and-drop. Built on LangChain, it lets developers compose chains, agents, and RAG pipelines by connecting modular components visually. Features real-time interaction, Python customization, one-click deployment, and export to LangChain code. Supports all major LLM providers, vector stores, and tools. With 146K+ GitHub stars, it bridges visual prototyping and production deployment.

Multi-agent programming framework inspired by the Actor model

Langroid is a lightweight Python framework from CMU and UW-Madison researchers for building LLM applications using a multi-agent programming paradigm inspired by the Actor Framework. Agents are first-class citizens that encapsulate LLM state, vector stores, and tools, then collaborate via message passing through hierarchical task delegation. With 3,900+ GitHub stars, Langroid works with any LLM provider and does not depend on LangChain or other frameworks.

Lightning-fast Rust-powered code editor

Lapce is an open-source code editor written in Rust, delivering sub-millisecond response times through native GPU rendering via wgpu. It features modal editing inspired by Vim, built-in LSP support for intelligent code completion, and a WASI-based plugin system supporting Rust, C, and AssemblyScript extensions. Includes integrated remote development over SSH, a built-in terminal, and split-pane layouts. Its rope-based text architecture ensures efficient handling of large codebases.

Sentry-style observability for AI agent conversations

Latitude is an agent observability platform for teams that need to inspect LLM traces, conversations, issues, and evaluation feedback in one workflow. Its public repo and docs position it as a Sentry-style monitor for AI agents, with semantic search, issue detection, annotations, MCP-assisted fixes, and cloud or self-hosted deployment paths for production debugging.

Twelve-lesson curriculum for building AI coding agents from scratch

Learn Claude Code is a comprehensive educational framework with 12 structured lessons teaching AI coding agent construction from first principles. With over 46,000 GitHub stars and 7,000 forks, it provides complete runnable Python implementations progressing from a 50-line bash agent to a 550-line skills agent with modular extensibility and subagent orchestration.

Memory-first coding agent that learns over time

Letta Code is a memory-first CLI coding agent that persists across sessions and improves over time. Unlike stateless tools like Claude Code or Codex, it works with long-lived agents remembering your codebase, preferences, and past interactions. Model-agnostic supporting Claude, GPT, Gemini, and more. Features git-backed context repositories, skill learning from experience, sleep-time reflection, and subagent orchestration. #1 model-agnostic OSS harness on Terminal-Bench.

Auto-generates interactive ER diagrams from database schemas

Liam ERD automatically generates beautiful, interactive entity-relationship diagrams from existing database schemas. It supports Rails schema.rb, PostgreSQL, Prisma, and raw SQL — with zero configuration required. A web version handles public repos instantly, while the CLI processes private repositories with CI/CD integration for keeping documentation in sync.

Web page quality auditing

Google's open-source automated tool for auditing web page performance, accessibility, SEO, best practices, and Progressive Web App compliance. Generates detailed reports with actionable improvement suggestions and scores from 0-100 for each category. Built into Chrome DevTools, available as a CLI tool, Node.js module, and via PageSpeed Insights web interface. Essential for web performance optimization and meeting Core Web Vitals thresholds that affect Google search rankings.

Build custom AI inference servers in pure Python

Open-source, FastAPI-based serving engine from Lightning AI for building custom inference APIs — models, agents, RAG, and pipelines — with built-in batching, streaming, and multi-GPU autoscaling.

Google's production on-device LLM inference framework

LiteRT-LM is Google's official open-source framework for running large language models on-device across Android, iOS, Web, Desktop, and Raspberry Pi. Already deployed in Chrome and Pixel hardware, it provides production-grade on-device LLM inference with 1.4K+ GitHub stars. Apache 2.0 licensed.

Open-source real-time voice, video, and AI agent infrastructure

LiveKit is an open-source WebRTC infrastructure platform for building real-time voice, video, and data applications. It powers ChatGPT Advanced Voice Mode and serves as the foundation for AI agent voice interactions. LiveKit provides server-side SDKs for Go, Python, Node.js, and Rust alongside client SDKs for every major platform. The Agents framework lets developers build voice-enabled AI assistants with speech-to-text, LLM processing, and text-to-speech pipelines in Python or Node.js.

Multi-LoRA inference server for serving hundreds of fine-tuned models

LoRAX is an inference server that serves hundreds of fine-tuned LoRA models from a single base model deployment. It dynamically loads and unloads LoRA adapters on demand, sharing the base model's GPU memory across all adapters. Built on text-generation-inference with OpenAI-compatible API. Enables multi-tenant model serving without per-model GPU allocation. Over 3,700 GitHub stars.

Free, open-source local AI inference engine

LocalAI is an open-source local AI inference engine with 44K+ GitHub stars that runs LLMs, image generation, audio transcription, and embeddings entirely on consumer hardware without GPU requirements. Provides an OpenAI API-compatible REST endpoint as a drop-in replacement, supporting 1000+ models including LLaMA, Mistral, and Phi families. Features include text-to-speech, speech-to-text, function calling, constrained grammar output, and multi-modal capabilities all running locally.

Open-source cross-platform file sharing over local network

LocalSend is a free, open-source application for secure peer-to-peer file and message sharing between nearby devices over your local network. It works on Windows, macOS, Linux, Android, iOS, and Fire OS without requiring an internet connection or third-party servers. Each device generates TLS/SSL certificates for encrypted HTTPS communication, making it a privacy-first alternative to AirDrop that works across all operating systems.

Open-source AI-powered log analysis by Salesforce

LogAI is an open-source log analysis platform by Salesforce Research that uses deep learning to detect anomalies in large-scale system logs. It provides research-backed autonomous log troubleshooting capabilities, applying ML models to identify patterns, cluster log events, and surface anomalies that would be invisible in manual log review across high-volume production environments.

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.

Official debugger for MCP server development

MCP Inspector is the official interactive developer tool from the Model Context Protocol team for testing, debugging, and validating MCP servers. It provides a visual interface to inspect available tools, test transport configurations, export configs for different clients, and verify protocol compliance during MCP server development.

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.

Security scanner for MCP servers against tool poisoning attacks

MCP-Scan is a security tool that scans MCP servers for vulnerabilities including tool poisoning, prompt injection, cross-origin escalation, and rug pull attacks. Acquired by Snyk in 2026, it is the first dedicated security scanner for the MCP ecosystem. It analyzes tool descriptions, permissions, and behavior patterns to detect malicious or compromised MCP servers before they can exploit AI agents.

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.