FreePDF

The application is a free PDF reader that can translate documents from one language to another and optionally answer questions based on the PDF content using large‑language‑model services. It supports translation between Chinese (including traditional), English, Japanese and Korean, and can generate a translated version of the file alongside the original. Users can select a translation engine such as Bing, Google, SiliconFlow, Ollama, or a custom OpenAI‑compatible service, and configure the source and target languages in a JSON settings file.

In addition to translation, the tool can invoke a question‑answer engine that processes the text of the PDF (or a specified page range) and returns answers in Chinese, guided by a system prompt that includes the document content. The QA engine can be disabled or linked to the same set of back‑ends used for translation.

The software runs on macOS (including ARM64) and Windows, is distributed under the AGPL‑3.0 license, and can be installed via Homebrew on macOS. It requires the DocLayout‑YOLO ONNX model for layout detection and a set of fonts for rendering translated text.