Open Source Tools

Human-friendly HTTP client

User-friendly CLI HTTP client for testing and debugging APIs with intuitive syntax, colorized output, and JSON highlighting. Simpler than curl with sensible defaults — auto JSON formatting, persistent sessions, and auth helpers. Also available as HTTPie Desktop (GUI) and HTTPie for Web (browser-based). Supports HTTPS, proxies, file uploads, and plugins. 34K+ GitHub stars. The developer-friendly curl alternative for API work.

Instant GraphQL and REST APIs on any database

Hasura auto-generates real-time GraphQL and REST APIs directly from your database schema—PostgreSQL, MySQL, SQL Server, MongoDB, and more. It provides fine-grained row-level and column-level access control, event triggers on database changes, remote schema stitching, and real-time subscriptions out of the box. Available as a managed cloud service or self-hosted, Hasura eliminates weeks of boilerplate API development while maintaining full control over authorization logic.

NLP and RAG pipeline framework by deepset

Haystack is an open-source AI orchestration framework by deepset for building production-ready LLM applications with explicit control over retrieval, routing, memory, and generation pipelines. Its component-based architecture lets developers chain specialized pieces into branching, looping pipelines for semantic search, RAG, QA, and autonomous agents. Integrates with OpenAI, Anthropic, Mistral, Cohere, Hugging Face, Azure, AWS Bedrock, and major vector stores.

Completely unstyled, accessible UI components for React and Vue by Tailwind Labs.

Headless UI is an open-source collection of completely unstyled, accessible UI components for React and Vue, created by the Tailwind CSS team. Provides WAI-ARIA compliant components like Menu, Listbox, Switch, Dialog, Popover, Tabs, and more. Designed to pair perfectly with Tailwind CSS.

A post-modern modal text editor

Helix is a post-modern modal text editor written in Rust, inspired by Kakoune and Neovim. It ships with built-in Tree-sitter support for syntax highlighting and structural editing across dozens of languages, native LSP integration for autocompletion and diagnostics, and multiple cursors as a first-class feature. Helix requires no plugin system or configuration to be productive out of the box, offering a selection-then-action editing model that reverses the Vim paradigm.

AI-native API gateway by Alibaba with MCP server hosting and LLM routing

Higress is an open-source AI-native API gateway developed by Alibaba that combines traditional API management with LLM-specific capabilities like token-based rate limiting, model routing, prompt caching, and MCP server hosting. Built on Envoy and Istio, it provides enterprise-grade traffic management while natively understanding AI workload patterns including streaming responses, long-lived connections, and multi-model fallback chains.

Agent memory system that learns, not just remembers

Hindsight is an agent memory system that enables AI agents to learn from experience rather than just store conversations. It organizes memories into three biomimetic categories: World knowledge for facts, Experiences for agent events, and Mental Models for learned understanding. The system provides retain, recall, and reflect operations backed by a temporal knowledge graph with parallel retrieval strategies including semantic, keyword, graph traversal, and temporal search.

The missing package manager for macOS

The default package manager for macOS (also available on Linux) that installs CLI tools, developer utilities, GUI applications (via Casks), and fonts with simple terminal commands. Massive repository of 7,000+ formulae and 5,000+ casks maintained by the community. Features dependency resolution, bottled (pre-compiled) packages for fast installs, automatic updates, and cleanup. Essential tool for any Mac developer's setup. 42K+ GitHub stars and the largest macOS package ecosystem.

Ultrafast web framework built on Web Standards for every runtime

Hono is a lightweight, ultrafast web framework built on Web Standards that runs on Cloudflare Workers, Deno, Bun, Node.js, AWS Lambda, and any JavaScript runtime. At just 12kB with zero dependencies, it delivers router performance matching raw platform speed. Hono provides first-class TypeScript support with RPC-style client for end-to-end type safety, built-in middleware for auth, CORS, caching, and OpenAPI generation, plus JSX support for server-rendered HTML.

Architect agent that builds with reusable components

Hope AI by Bit Cloud is an architect agent with 18,000+ GitHub stars on the Bit platform that builds professional software using reusable components. It proposes entire software architectures, generates code with documentation and test coverage, and ensures clean component patterns, addressing the architectural integrity gap that most vibe-coding tools ignore when generating code.

AI Lakehouse with Feature Store for real-time ML

Hopsworks is a data-intensive AI platform combining a Python-centric Feature Store with MLOps capabilities for production ML systems. Provides sub-millisecond feature retrieval powered by RonDB, dual offline and online storage for batch and real-time inference, experiment tracking, model registry, and deployment pipelines. Available as managed cloud on AWS, Azure, and GCP, self-hosted on Kubernetes, or serverless platform.

ACP skill definitions giving coding agents HuggingFace ML superpowers

Hugging Face Skills is the official collection of ACP skill definitions that give AI coding agents access to HuggingFace ML capabilities. The 13 skills cover LLM fine-tuning with TRL, vision model training, dataset management, model evaluation, and cloud job submission on HF infrastructure. Compatible with Claude Code, Codex, Gemini CLI, and Cursor via a single npx command.

CLI tool for running and testing HTTP requests from plain text files

Hurl is a command-line tool that runs HTTP requests defined in simple plain text files with built-in assertions for testing. It supports GET, POST, PUT, GraphQL, multipart, cookies, authentication, and response validation with JSONPath, XPath, and regex. Chain multiple requests with variable capture between steps. 17,000+ GitHub stars, Apache 2.0 license, written in Rust for speed. Ideal for API testing in CI/CD pipelines as a lightweight alternative to Postman collections.

Electron-based terminal with plugin ecosystem

Terminal emulator built on web technologies (HTML/CSS/JS) using Electron. Extensible via npm packages with a vibrant plugin and theme ecosystem. Created by Vercel with 43k+ GitHub stars. Offers split panes, configurable hotkeys, and a fully customizable UI that appeals to developers who want a modern, hackable terminal experience.

Open-source natural-language browser automation framework for AI agents

An AGPL-3.0 TypeScript framework that drives a real browser from natural-language tasks — the self-hostable OSS framework from Hyperbrowser, distinct from the vendor's paid cloud browser product.

Local-first AI notepad for meetings and voice notes

Hyprnote is a local-first AI notepad designed for capturing and processing meeting notes and voice recordings. It runs entirely on-device for privacy, transcribes audio using local models, and generates structured summaries, action items, and follow-ups. Built with Rust and Tauri for native desktop performance. Over 8,000 GitHub stars with strong privacy-focused community adoption.

Open-source secrets management platform

Infisical is an open-source secrets management platform with 16K+ GitHub stars for syncing environment variables and secrets across teams, CI/CD pipelines, and infrastructure. Features end-to-end encryption, automatic secret rotation, dynamic secrets, access controls with audit logs, and native integrations with AWS, GCP, Azure, Kubernetes, Docker, GitHub Actions, and Vercel. Replaces scattered .env files with a centralized, encrypted secrets store accessible via dashboard, CLI, SDK, or API.

Open-source API client

Open-source API client by Kong for designing, debugging, and testing REST, GraphQL, gRPC, and WebSocket APIs. Features a clean interface with environment variables, authentication helpers, code generation, cookie management, and response timeline. Supports OpenAPI and Swagger specs for design-first workflows. Git Sync for version-controlled API collections. Available on macOS, Windows, and Linux. A popular alternative to Postman with stronger focus on privacy and local-first usage.

Structured LLM outputs with validation

Instructor is the most popular Python library for extracting structured, validated data from large language models, with over 3 million monthly downloads and ports across Python, TypeScript, Go, Ruby, Elixir, and Rust. It uses Pydantic models to define output schemas and automatically handles validation, retries, and error correction when the LLM output does not match. Instructor patches existing client libraries instead of replacing them, preserving full access to the underlying API.

Leading open-source service mesh for Kubernetes microservices

Istio is the most widely adopted open-source service mesh for Kubernetes, providing traffic management, security, and observability for microservice architectures. It uses Envoy proxy sidecars to intercept and manage service-to-service communication with mutual TLS, fine-grained traffic routing, circuit breaking, and distributed tracing. CNCF Graduated project used in production by Google, IBM, and Salesforce.

Visualize JSON, YAML, XML, and CSV as interactive graphs

JSON Crack transforms structured data files into interactive, visual graphs that make complex nested data easy to understand. Paste or import JSON, YAML, XML, CSV, or TOML and instantly see the data as a navigable node graph with collapsible sections, search, and path highlighting. All processing happens client-side with no server storage.

Pretty-print JSON in the browser

Open-source browser extension that automatically pretty-prints JSON responses in the browser tab. Supports collapsible nodes, syntax highlighting, and raw/formatted toggle. Essential developer tool for anyone who works with APIs regularly, turning unreadable JSON blobs into navigable, color-coded trees that make debugging API responses significantly faster and less error-prone.

Offline-first AI assistant for local inference

Jan is an open-source offline-first AI assistant with 25K+ GitHub stars running LLMs locally without sending data externally. Features a ChatGPT-like interface with one-click model downloads from Hugging Face, conversation management, customizable prompts, and an OpenAI-compatible local API server. Supports GGUF models via llama.cpp with GPU acceleration on NVIDIA and Apple Silicon. Built with Electron for macOS, Windows, and Linux with full data privacy.

BEAM/Elixir-native framework for durable multi-agent systems

Jido is an Elixir-native AI agent framework that leverages the BEAM virtual machine's concurrency and fault-tolerance for building durable, distributed multi-agent systems. It provides primitives for agent lifecycle management, skill composition, and message-based coordination. Designed for teams running Elixir in production who need agent capabilities. Apache-2.0 with 1,600+ GitHub stars.

Open-source post-building layer for agents — tracing, evals, and online monitoring

Judgeval is the open-source post-building layer for AI agents from Judgment Labs, providing OpenTelemetry-based tracing, hosted and custom evaluation scorers, and online behavior monitoring for LLM-powered applications. Instrument any function with a single decorator, score live production traffic against faithfulness and instruction-adherence checks, and feed real-world failures back into reinforcement learning or supervised fine-tuning loops.

Cloud-native POSIX filesystem on object storage

JuiceFS is a high-performance distributed POSIX filesystem built on object storage like S3 and metadata engines like Redis or MySQL. It enables seamless data sharing across thousands of clients with low latency and elastic throughput. JuiceFS ships with a Kubernetes CSI driver, Hadoop SDK compatibility, and FUSE mount support for AI training, big data analytics, and shared storage workloads. Apache 2.0 licensed with 13K+ GitHub stars.

Interactive computing notebooks for data science

Jupyter is the open-source interactive computing platform providing notebook interfaces for data science, ML, scientific computing, and education. Notebooks combine live code, equations, visualizations, and narrative text. Supports 40+ languages via kernels including Python, R, Julia, and Scala. JupyterLab provides a modern IDE-like interface. JupyterHub enables multi-user deployments. The standard tool for computational research and data exploration worldwide.

Terminal dashboard for Kubernetes

K9s is an open-source terminal UI with 28K+ GitHub stars for managing Kubernetes clusters interactively. Provides a real-time dashboard with resource navigation, log tailing, shell access to pods, port forwarding, and RBAC visualization — all from the terminal without kubectl commands. Features Vim-style navigation, custom resource views, plugin system, cluster metrics, and multi-cluster support. Dramatically reduces the complexity of daily Kubernetes operations for developers and SREs.

Kubernetes-native model inference platform

KServe is an open-source Kubernetes-native platform for deploying and managing ML model inference at scale. It provides standardized inference protocols, autoscaling including scale-to-zero, canary rollouts, A/B testing, and multi-model serving. KServe supports all major ML frameworks including TensorFlow, PyTorch, scikit-learn, XGBoost, and LLM runtimes like vLLM and Triton through pluggable serving runtimes.

Heterogeneous CPU-GPU inference and SFT for large MoE models

Open-source framework for running and fine-tuning large Mixture-of-Experts models with heterogeneous CPU-GPU execution, optimized kernels, limited VRAM and SGLang or LLaMA-Factory integrations.

JavaScript framework for building and visualizing multi-agent workflows on a Kanban board

KaibanJS is an MIT-licensed JavaScript framework for defining AI agents, tasks, tools, and teams, then orchestrating their work through a Kanban-inspired runtime and visual board. It can run inside Node.js, React, or Next.js projects, supports custom UIs and headless workflows, and provides real-time task-state visibility for multi-agent applications.

Deploy web apps anywhere

Zero-downtime deployment tool created by 37signals (Basecamp/HEY) that deploys Docker containers to any VPS or bare metal server over SSH without requiring Kubernetes. Manages rolling deploys, health checks, SSL via Let's Encrypt, container registry, and load balancing with Traefik. Simple YAML-based config. Ideal for small teams deploying Rails, Node.js, or any Dockerized app. Ships as a Ruby gem. 12K+ GitHub stars and a growing alternative to complex container orchestration.

Open-source AIOps alert management platform

Keep is an open-source AIOps platform that provides a single pane of glass for all alerts from monitoring tools like Datadog, PagerDuty, Grafana, and 50+ integrations. It uses AI to correlate, deduplicate, and enrich alerts, reducing noise and helping on-call teams focus on real incidents. Keep includes workflow automation, bidirectional sync with ticketing systems, and a modern web dashboard.

Declarative orchestration for data, AI, and infra

Kestra is an open-source orchestration platform that uses declarative YAML to define event-driven and scheduled workflows for data pipelines, infrastructure automation, and AI workloads. With over 1,200 plugins, it connects to databases, cloud services, APIs, and SaaS tools without custom glue code. Kestra reached version 1.0 LTS with agentic AI capabilities, SDKs for Python, TypeScript, Java, and Go, and SOC 2 compliance. Clients include Leroy Merlin, Huawei, Tencent, and Decathlon.

Open-source AI second brain with deep research and RAG

Khoj is an open-source personal AI app that serves as a self-hostable second brain. It connects to your documents — PDFs, Markdown, Notion, Word — and uses RAG to answer questions grounded in your knowledge base. Supports any local or cloud LLM including Llama, Claude, GPT, and Gemini. Features custom agents, scheduled automations, deep research mode, semantic search, and Obsidian, Emacs, and WhatsApp integrations. Over 33,000 GitHub stars, YC-backed.

MCP integration platform for agent tool use at scale

Klavis AI is an Apache-2.0 MCP integration platform for teams connecting AI agents to external SaaS tools and APIs. The public repo and official docs position it as infrastructure for reliable tool access at scale, so it fits teams that want reusable MCP connectors without treating every integration as a one-off script or custom OAuth maintenance project.

SQL query builder for Node.js

Flexible SQL query builder for Node.js supporting PostgreSQL, MySQL, SQLite, Oracle, and MSSQL. Chainable API for constructing queries with parameterized bindings. Features schema builder, migration system, seed files, transaction support, and connection pooling. Foundation for ORMs like Bookshelf.js and Objection.js. One of the most established query builders in the Node.js ecosystem.

Find unused files, dependencies, and exports in JavaScript and TypeScript projects

Knip is an open-source CLI tool that detects unused files, dependencies, devDependencies, and exports in JavaScript and TypeScript codebases. It analyzes the full dependency graph to identify dead code that accumulates over time — especially relevant for AI-generated codebases where unused artifacts pile up faster than manual cleanup can handle. With over 10,800 GitHub stars, it has become a standard code hygiene tool in the JS/TS ecosystem.

Terminal AI coding agent with multi-model and AGENTS.md support

Open-source terminal coding agent (npm `@shareai-lab/kode`) that understands your codebase, edits files, and runs commands across 20+ AI models, with native AGENTS.md and legacy `.claude`/`CLAUDE.md` compatibility.

Kotlin-native AI agent framework by JetBrains with MCP support

Koog is JetBrains official Kotlin-native framework for building predictable, fault-tolerant AI agents. It provides structured agent workflows with MCP protocol support, type-safe tool definitions, and deterministic execution patterns designed for JVM production environments. As the first production-grade Kotlin agent framework, it fills the gap in a JVM ecosystem dominated by Python-based alternatives and integrates naturally with existing Kotlin and Java backend infrastructure.

RAG-based document QA with multi-user support and agent reasoning

Kotaemon is an open-source RAG-powered document question-answering interface backed by Cinnamon AI. It supports multi-user workspaces with access controls, advanced retrieval pipelines including hybrid search and knowledge graph extraction, and agentic reasoning for complex multi-step queries. The web UI handles PDFs, Office documents, and images with citations pointing to exact source passages, making it suitable for both individual research and team knowledge management.

Polyglot document intelligence framework with Rust core

Kreuzberg is a polyglot document intelligence framework with a high-performance Rust core that extracts text, metadata, images, and structured data from 91+ file formats. Available for Python, Ruby, Java, Go, PHP, C#, TypeScript, plus CLI, REST API, and MCP server. Features multiple OCR backends (Tesseract, EasyOCR, PaddleOCR), table extraction with structure preservation, and native async support.

CNCF Sandbox chaos engineering framework for Kubernetes resilience

Krkn is a CNCF Sandbox chaos engineering tool that tests Kubernetes cluster resilience by injecting controlled failures. It simulates pod kills, node failures, network partitions, CPU/memory pressure, and zone outages. Krkn-AI adds AI-powered scenario generation that suggests chaos experiments based on cluster topology. Supports CI/CD integration for automated resilience testing in deployment pipelines.

Kubernetes operator for serving AI inference workloads

KubeAI is an Apache-2.0 Kubernetes operator for deploying and scaling AI inference workloads, including LLMs, embeddings, reranking, and speech-to-text. It gives platform teams OpenAI-compatible endpoints, model proxy/controller primitives, model caching, scale-from-zero behavior, and cluster-native resource management for self-hosted inference on Kubernetes.

Modern application delivery platform for Kubernetes

KubeVela is a CNCF incubating project that provides a modern application delivery platform built on Kubernetes and the Open Application Model. It abstracts away infrastructure complexity by letting developers define applications declaratively with components, traits, and policies, while platform teams manage delivery workflows. KubeVela supports multi-cluster deployment, canary rollouts, GitOps integration, and extensible addon system.

Open-source MLOps platform for Kubernetes

Kubeflow is a CNCF open-source MLOps platform with 14,000+ GitHub stars for deploying and managing machine learning workflows on Kubernetes. It provides notebooks for experimentation, scalable training pipelines with distributed computing support, model serving with autoscaling, and comprehensive pipeline orchestration for teams running AI/ML workloads in cloud-native environments.

Type-safe SQL query builder for TS

Type-safe SQL query builder for TypeScript that provides auto-completion and compile-time type checking without the abstraction overhead of a traditional ORM. Write queries that map directly to SQL while getting full TypeScript inference from your database schema. Supports PostgreSQL, MySQL, and SQLite with migrations, transactions, and raw SQL escape hatches. Lightweight with zero dependencies. Ideal for developers who want SQL control with TypeScript safety. Growing Knex.js alternative.

Quantize and compress LLMs for optimized vLLM deployment

Open-source, Hugging Face-compatible library for quantizing and compressing LLMs (W8A8, W4A16, NVFP4/MXFP4, KV-cache and attention quantization, expert pruning) into vLLM-ready `compressed-tensors` checkpoints.