Extend UI

Jun 15, 2026 · via sidebar.io

Open-source React UI kit for document-heavy apps with viewers and e-signing.

Saves designers and developers time building document workflows; pre-built components for PDF, spreadsheets, and e-signing reduce heavy lifting in enterprise or SaaS apps.

ReactUI KitComponentsNo-code

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Deep divePro

Extend UI is an open-source React component library purpose-built for document-centric applications — think PDF viewers, spreadsheet renderers, e-sign flows, and file uploaders. Rather than forcing teams to stitch together a dozen separate libraries, it offers a cohesive kit for the specific, often-painful UX territory of handling business documents inside web apps.

Why it stands out

The narrow, honest focus is actually its strength — most UI kits ignore document workflows entirely, leaving teams to hack together janky PDF embeds and file upload states from scratch. Extend UI treats this as a first-class design problem.

Best for

Product designers embedded in B2B SaaS teams shipping document-heavy features like contract management, data import flows, or file review tools.

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