Duck.ai, launched by DuckDuckGo in early 2025, is an AI chat service that allows users to converse with models like GPT-5 or Claude Opus without registering an account. It is accessible at duck.ai, through the DuckDuckGo browser, or via desktop browser extensions. The service routes every conversation through DuckDuckGo's anonymizing proxy, stripping identifying information before reaching the model provider, and providers like OpenAI and Anthropic are contractually prohibited from using chats for training. Duck.ai offers free multi-model access, but free models are mid-tier and usage limits are vague. Paid plans bundle several services together, with no standalone AI plan: the Plus plan costs $9.99/month or $99.99/year, and the Pro plan costs $19.99/month or $199.99/year. The $9.99 Plus plan is noted as hard to argue with if a VPN and identity protection are also needed.