Open Source PDF SDK
An open source PDF SDK gives you the building blocks to render, search, and annotate PDF documents while keeping full control over UX, data, and roadmap.
What it is: a modular stack for rendering, search, selection, and annotations.
Who it's for: product teams building document readers on web or mobile.
When to use: you need full UX control and long-term ownership.
When not to use: you need heavy PDF editing or enterprise compliance features out of the box.
Use cases
- In-app document readers (contracts, manuals, reports).
- Knowledge products that ship on web and React Native.
- White-labeled viewers that must match your brand.
Papyrus is actively developed as a modular SDK on NPM, with separate packages for core logic, engines, and UI. It is designed for production readers, not demos.
What you get from a PDF SDK
- Rendering and text layer support for selection, highlights, and outlines.
- Reader UI components like toolbars, sidebars, and pagination.
- State and events for annotations, search, and navigation.
- Theming so the viewer matches your product.
High-level architecture
Papyrus is designed as a composable stack:
- Core: shared state + events for reader UX.
- Engines: PDF.js on web and native PDF on mobile.
- UI kits: React and React Native components.
How Papyrus fits
Papyrus is an open source PDF SDK with a shared core, pluggable engines, and UI kits for React and React Native. It focuses on real reader workflows: selection, search, highlights, and annotations.
Key points:
- MIT license with no usage caps.
- Engine-agnostic core (PDF.js on web, native on mobile).
- Ready-to-use UI components for web and mobile readers.
- Multi-format support (PDF, EPUB, TXT) if your roadmap needs it.
How it compares to other PDF SDKs
- Engine-only stacks (PDF.js only): fast to start, but you still build UI and state.
- Commercial PDF SDKs: strong features, but licensing and lock-in.
- Closed-source viewers: limited customization and long-term control.
- Papyrus: open source, composable, and built for reader UX.
Evaluation checklist
- Open source license with clear terms
- Rendering quality and text layer accuracy
- Search, outline, and page navigation
- Annotations and selection events
- Web and mobile parity
- Active docs and examples
If you're evaluating an open source PDF SDK for a real product, the best way to validate fit is to run the quickstart and test your core reader flows.