Best Developer Tools open-source projects

yt-dlp is a command-line tool designed for downloading audio and video content from a vast array of online platforms, offering extensive customization options.

Ollama is the simplest way to download and run open large language models on your own machine. A single command pulls a model and starts chatting; a local API lets your apps use it without any cloud service.

This repository provides a highly popular collection of agent 'skills'—small, adaptable scripts and prompts—designed to improve the interaction and output quality of AI coding assistants by applying robust engineering principles.

Agent Skills is an open-source AI agent skills collection from Addy Osmani: 24 structured workflows that push AI coding agents through the spec-plan-build-test-review-ship discipline a senior engineer would follow. Instead of one-off prompts, each skill is a step-by-step process with verification gates, so the agent writes a PRD before code and proves tests pass before shipping.

Chrome DevTools MCP is an MCP server that gives a coding agent access to a live Chrome browser through the full Chrome DevTools toolset. Your agent — Claude, Cursor, Copilot, or Antigravity — can record performance traces, read network requests and console messages, take screenshots, and automate actions with Puppeteer.

Continue is an open-source coding agent that shipped as a CLI, a VS Code extension, and a JetBrains plugin. It's worth knowing up front: the README states the repository is now read-only and no longer actively maintained after a final 2.0.0 release.

codebase-memory-mcp is a code intelligence MCP server, written in C, that indexes a codebase into a persistent knowledge graph of functions, classes, and call chains. Once indexed, your coding agent runs structural queries — trace this call path, find dead code, show the architecture — instead of grepping file by file. The README reports full-indexing an average repo in milliseconds and the Linux kernel in about three minutes, with sub-millisecond graph queries.

SimpleX Chat private messaging routes your conversations through relay servers without giving you any account or user ID at all. The README calls it the first messaging network that operates without user identifiers of any kind. There's no phone number, no username, and no hidden account ID a server could use to link who you talk to. It ships apps for Android, iOS, desktop, and a terminal CLI for Linux, macOS, and Windows, all built on double-ratchet end-to-end encryption with an extra encryption layer.

OmniRoute is a self-hostable AI gateway that puts one endpoint in front of many model providers. You point coding agents like Claude Code, Cursor, or Cline at it, and it routes requests across providers — including free tiers — with automatic fallback when one is unavailable.

Agent Orchestrator (AO) is an open-source harness for running AI coding agents in parallel. It gives terminal agents like Claude Code, Codex, Cursor, Aider, and Goose isolated workspaces, live terminals, and automatic loops that route CI failures, review comments, and merge conflicts back to the right agent.

Agent Skills is an open-source AI agent skills collection from Addy Osmani: 24 structured workflows that push AI coding agents through the spec-plan-build-test-review-ship discipline a senior engineer would follow. Instead of one-off prompts, each skill is a step-by-step process with verification gates, so the agent writes a PRD before code and proves tests pass before shipping.

This repository provides a highly popular collection of agent 'skills'—small, adaptable scripts and prompts—designed to improve the interaction and output quality of AI coding assistants by applying robust engineering principles.

yt-dlp is a command-line tool designed for downloading audio and video content from a vast array of online platforms, offering extensive customization options.

OmniRoute is a self-hostable AI gateway that puts one endpoint in front of many model providers. You point coding agents like Claude Code, Cursor, or Cline at it, and it routes requests across providers — including free tiers — with automatic fallback when one is unavailable.

Agent Orchestrator (AO) is an open-source harness for running AI coding agents in parallel. It gives terminal agents like Claude Code, Codex, Cursor, Aider, and Goose isolated workspaces, live terminals, and automatic loops that route CI failures, review comments, and merge conflicts back to the right agent.

SimpleX Chat private messaging routes your conversations through relay servers without giving you any account or user ID at all. The README calls it the first messaging network that operates without user identifiers of any kind. There's no phone number, no username, and no hidden account ID a server could use to link who you talk to. It ships apps for Android, iOS, desktop, and a terminal CLI for Linux, macOS, and Windows, all built on double-ratchet end-to-end encryption with an extra encryption layer.

Continue is an open-source coding agent that shipped as a CLI, a VS Code extension, and a JetBrains plugin. It's worth knowing up front: the README states the repository is now read-only and no longer actively maintained after a final 2.0.0 release.

codebase-memory-mcp is a code intelligence MCP server, written in C, that indexes a codebase into a persistent knowledge graph of functions, classes, and call chains. Once indexed, your coding agent runs structural queries — trace this call path, find dead code, show the architecture — instead of grepping file by file. The README reports full-indexing an average repo in milliseconds and the Linux kernel in about three minutes, with sub-millisecond graph queries.