Show HN: Extend UI – open-source UI kit for modern document apps

	Show HN: Extend UI – open-source UI kit for modern document apps(extend.ai)
	241 points by kbyatnal 1 day ago \| 79 comments
	tl;dr: Extend UI is an open-source React component library for building document-centric apps, offering viewers for PDF, DOCX, XLSX, and CSV files. It includes additional components like bounding box citations, file upload, e-signatures, document splits, schema builders, and DOCX editing, aimed at user-facing flows, AI agents, and internal tools.
	HN Discussion: ↓Demo site has terrible performance and lags on modern hardware ↓Missing basic functionality like sorting, search, and keyboard navigation ↑Useful tool for AI document workflow automation and parsing visualization ↑Bounding box and citation components solve genuinely hard problems ↓Should be framework-agnostic web components instead of React-only