MinerU is a production-grade document parsing engine that converts PDFs, images, and Office documents (DOCX, PPTX, XLSX) into structured Markdown and JSON. It supports multiple backends: a fast pipeline (layout analysis + OCR + formula/table recognition), a high-accuracy hybrid mode combining VLM and OCR, and a pure VLM mode using vLLM/LMDeploy. The system is deployed as a CLI tool, FastAPI service, Gradio web UI, or Docker container, with integrations for RAG frameworks like LangChain, LlamaIndex, and Dify. The codebase is well-architected with clean abstractions for data I/O (file/S3), model initialization (singleton pattern), and output generation (client-side rendering). It handles 109 languages and includes specialized modules for mathematical formula recognition (UniMERNet), table structure recovery (SLANet+/UNet), and office document normalization. While the code is actively maintained and functionally rich, it carries some technical debt from its PaddleOCR heritage (vendored code, eval-based builders) and has a complex optional dependency matrix for hardware accelerators.
Dolphin is a document image parsing tool that uses a two-stage analyze-then-parse approach with a VLM (Qwen2.5-VL). It takes images or PDFs, performs layout analysis to detect elements (text, tables, formulas, code, figures) with reading order, then parses each element in parallel batches. Outputs structured JSON and Markdown with visualized layout. The codebase is well-structured, offering CLI entry points for page-level, element-level, and layout-only parsing. It demonstrates good engineering practices with batching, coordinate mapping, and post-processing for formula/special characters. The core implementation wraps the Hugging Face Qwen2.5-VL model and includes utility modules for layout string parsing, PDF conversion, and markdown generation. The architecture is a CLI application with minimal coupling, making the utility modules potentially reusable across document parsing projects.