Twinny is a VS Code extension that provides AI-assisted code completion and conversational assistance, functioning as a free alternative to GitHub Copilot. It supports integration with numerous LLM providers including OpenAI, Anthropic, Ollama, Deepseek, Cohere, Mistral, Perplexity, Groq, and OpenRouter. The extension uses workspace embeddings for context-aware suggestions and includes features such as fill-in-the-middle code completion, chat-based code discussions, git commit message generation, and a decentralized P2P inference network called Symmetry.