OpenThorn is a free, open-source AI website builder. Connect your own API key from a variety of providers — OpenAI, Anthropic, Gemini, Ollama, and more — and an AI agent plans, builds, and verifies a complete website. Everything compiles and previews instantly in your browser, then deploys with one click. No subscription, no markup on tokens, no lock-in: you pay your provider directly and keep full ownership of the code. An open alternative to Lovable, Bolt, and Base44.