Frequently asked questions.

LangBox is free during public preview, within the available model allowance. Guests receive trial credits; signed-in accounts can receive 2,000,000 tokens per 30-day period. Your own API key may incur provider charges. Any future pricing changes will be announced.

No. You can start reading, looking up words, and using LangBox-provided AI models with guest trial credits, without registering or signing in manually. You can also use your own API key. Sign in to receive the monthly model allowance and sync your vocabulary and practice progress across devices.

With Personalized learning recommendations enabled, translations made with LangBox models can be saved to your learning space when model credits remain. This also applies to guests; translations made with your own API key are not captured by this workflow. Saved data can include text, translations, source pages, and practice progress. Model requests send the necessary text to the selected provider. You can turn off capture in settings; see the Privacy Policy for data handling and deletion options.

Yes. OpenAI, Anthropic Claude, Google Gemini, and custom OpenAI-compatible endpoints are supported. Keys are stored locally in your browser and used to authenticate requests to your selected provider. Provider charges and usage limits apply.

The UI is available in English, Simplified Chinese, Traditional Chinese, Japanese, Korean, and Spanish. Reading and translation support virtually any language pair you configure. Built-in curricula currently cover IELTS, CEFR A1–C2, and workplace Japanese and Korean.

LangBox supports reading with the original text in view. Drawing on Comprehensible Input (i+1), it combines paragraph translations with in-page lookups and target-language definitions to help you understand unfamiliar expressions in context.