Show HN: Extend UI – open-source UI kit for modern document apps
Open-source UI kit for document processing agents just hit MIT. 14 components, battle-tested on millions of pages daily.
Why it matters
Extend.ai is releasing production-ready document viewer components that address a real gap in the market—most existing solutions lack the polish and edge-case handling needed for AI-powered document workflows at scale. This lowers the barrier for builders shipping document intake, processing agents, and e-signature flows.
The key facts
12 to know14 open-source UI components (MIT licensed)
Supports PDF, DOCX, XLSX viewers
Features: bounding box citations, file upload, e-signature
Extend.ai processes millions of pages daily
Battle-tested on internal production system
Designed for document processing agents and real-time user-facing intake flows
14 open-source UI components for PDF, DOCX, XLSX viewers
MIT licensed and fully customizable
Built from Extend's internal tooling for their own document processing
Supports bounding box citations, file upload, e-signature functionality
Processing millions of pages daily at scale according to creators
Published on Hacker News (niche developer audience)
Go to the source
Hacker Newsextend.ai
Publisher excerpt: We're open-sourcing 14 components & examples today for PDF, DOCX, and XLSX viewers, plus bounding box citations, file upload, e-signature, and more. It's MIT licensed and fully customizable. Demo video here: When we started, we tried every file viewer and document component library we could find.…