Mozilla PDF.js
Mozilla PDF.js is a free platform for parsing and rendering PDF files using web standards.
What Mozilla PDF.js is
Mozilla PDF.js is a free platform for parsing and rendering PDF files using web standards. Developers can use its display API to render documents and retrieve document information, or adapt the viewer layer to create a custom interface. That viewer is used in Firefox and project browser extensions. PDF.js can display annotations, add some annotation types, and fill forms, but it has no OCR support. The project targets HTML5-compliant browsers and offers a legacy build, though PDF feature support varies with browser and version. Prebuilt builds are available, and jsDelivr, cdnjs, and unpkg host the library. Developers can also clone and build it locally; some browsers require a local web server to open PDFs rather than using file URLs. Cross-origin requests are blocked by default, so using CORS or a server proxy may be necessary. For large documents, rendering only visible pages can reduce memory use. PDF.js is licensed under Apache 2.0, and its documentation under CC BY-SA 2.5.
Good
- Display API renders PDFs and retrieves document information.
- Viewer layer can be adapted for a custom interface.
- Supports form filling and some annotation types.
- Free and licensed under Apache 2.0.
Watch out
- Does not provide OCR.
- Cross-origin requests are blocked by default.
- Some local use requires a web server.
Who it suits
PDF.js suits developers who want to embed PDF rendering or build a custom viewer. It is also relevant to contributors interested in the community-driven project.
Verdict
PDF.js offers a free route to PDF rendering and viewer integration, with APIs and prebuilt builds available. Check browser compatibility and account for its OCR absence and cross-origin constraint.
Plans and prices
From Mozilla PDF.js's own pricing page, checked 7 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| PDF.js | Free | Open-source PDF parsing and rendering platform · Apache 2.0 license |
The facts
Each one read from Mozilla PDF.js's own pages, with the date it was checked.
What it does
- Annotations
- PDF.js renders annotations for viewing and supports adding a subset of annotation types.checked 7 Oct 2026
- Annotation tools
- Yeschecked 24 Sep 2026
- API
- The display layer exposes an API for rendering PDFs and retrieving document information.checked 7 Oct 2026
- Cross-origin constraint
- PDF.js cannot make cross-origin requests by default; the FAQ describes CORS or a server proxy as possible approaches.checked 7 Oct 2026
- Distribution
- Prebuilt builds are available, and the project lists jsDelivr, cdnjs, and unpkg as CDNs hosting PDF.js.checked 7 Oct 2026
- Form filling
- Yeschecked 24 Sep 2026
- Integrations
- PDF.js is built into Firefox 19 and later, and the project provides a Chromium browser extension.checked 7 Oct 2026
- Intended users
- The project describes itself as community-driven and invites contributors, while its library and viewer documentation gives developers ways to embed or build on PDF.js.checked 7 Oct 2026
- Large documents
- The FAQ recommends rendering only visible pages to reduce memory use when working with many high-resolution pages.checked 7 Oct 2026
- License
- PDF.js is licensed under Apache 2.0, and its documentation is licensed under CC BY-SA 2.5.checked 7 Oct 2026
- OCR support
- nonechecked 24 Sep 2026
- Purpose
- PDF.js is a web standards-based platform for parsing and rendering PDF files.checked 7 Oct 2026
- Security reporting
- The project directs reports about the library or Firefox PDF Viewer to Bugzilla and reports about the Chrome extension to GitHub’s private vulnerability reporting form.checked 7 Oct 2026
- Self hosting
- The project documents cloning and building PDF.js locally, and says a local web server is needed because some browsers disallow opening PDFs through file URLs.checked 7 Oct 2026
- Support
- The project points users to GitHub issues for technical problems and its Matrix room for questions or guidance.checked 7 Oct 2026
- Viewer
- Its viewer layer provides the user interface used in Firefox and project browser extensions, and can be adapted to build a custom viewer.checked 7 Oct 2026
Where it runs
- Browser support
- The project aims to support HTML5-compliant browsers and provides a legacy build for older browsers; PDF feature support varies by browser and version.checked 7 Oct 2026
- Platform support
- webchecked 24 Sep 2026
Money
- Free plan
- Yeschecked 24 Sep 2026
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