When you're on the free hosted plan, text you send for AI scanning or interpretation goes to Google's Gemini paid API. This is a paid commercial tier, not the free consumer product, and Google's paid API terms don't allow training on your inputs. When you're on the Pro plan, your text goes to Anthropic's Claude API instead. Anthropic's commercial terms prohibit training on customer content. See Google's API terms and Anthropic's commercial terms for details.
If you bring your own API key, your text goes directly to whichever provider you chose. KRW's Worker proxies the request but doesn't store the key or the text. The key is hashed for per-user rate limiting and never persisted in raw form. Your manuscript content, marks, dictionary, and revision history all stay in IndexedDB on your device and are never sent to a KRW-owned database.