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Mozilla PDF.js

Free plan APIExtensionLinuxSelf-hostedWeb

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Mozilla PDF.js's own site

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 layer API to render documents and retrieve information, or adapt the viewer layer when building a custom PDF interface. That viewer is used in Firefox and project browser extensions. PDF.js can display annotations and add some annotation types, and it supports form filling; it does not include OCR. The project targets HTML5-compliant browsers and offers a legacy build, although PDF feature support varies by browser and version. Prebuilt builds are available, along with hosted copies through jsDelivr, cdnjs and unpkg. Developers can also clone and build it locally; some browsers require serving the files from a local web server rather than opening PDFs through file URLs. Cross-origin requests are blocked by default, with CORS or a server proxy described as possible approaches. For large documents, rendering only visible pages can reduce memory use. PDF.js uses the Apache 2.0 license, and its documentation is under CC BY-SA 2.5.

Who it suits

PDF.js is for developers who need PDF parsing or rendering in web projects, or who want to adapt its viewer. The project also invites community contributions.

What it does well

  • Provides an API for rendering PDFs and retrieving document information
  • Viewer layer can be adapted for a custom interface
  • Supports form filling and some annotation types
  • Prebuilt builds and CDN-hosted copies are available

What to know first

  • Does not provide OCR support
  • Cross-origin requests are blocked by default
  • PDF feature support varies by browser and version
  • Some local use requires a web server

Limits

The free PDF.js plan is an open-source PDF parsing and rendering platform under Apache 2.0. It has no OCR support, and annotation creation is limited to a subset of annotation types.

Plans

PlanBilled and limitsPrice
PDF.jsOpen-source PDF parsing and rendering platform · Apache 2.0 licenseFree

As mozilla.github.io lists them, read 7 Oct 2026. The maker's own page has the final word.

Getting started

  1. Visit the PDF.js website.
  2. Choose a prebuilt build or a hosted copy from jsDelivr, cdnjs, or unpkg.
  3. For local use, clone and build the project, then serve it through a local web server.
  4. Adapt the viewer layer or use the display API in your project.

Verdict

PDF.js offers a free, open-source foundation for PDF rendering, with both an API and an adaptable viewer. Developers should account for browser differences, the lack of OCR and the default cross-origin restriction.

Questions

How much does PDF.js cost?

PDF.js is free. Its listed plan is free.

Does PDF.js support OCR?

No. OCR support is listed as none.

Can PDF.js fill forms and handle annotations?

It supports form filling, displays annotations, and can add a subset of annotation types.

Which platforms does PDF.js support?

Its listed platforms are API, extension, Linux, self-hosted, and web.

What license does PDF.js use?

The library is licensed under Apache 2.0. Its documentation uses CC BY-SA 2.5.

Where can developers get help?

The project points users to GitHub issues for technical problems and its Matrix room for questions or guidance.

Facts from Mozilla PDF.js's own pages

Annotations
PDF.js renders annotations for viewing and supports adding a subset of annotation types. · github.com, 7 Oct 2026
Annotation tools
Yes · mozilla.github.io, 24 Sept 2026
API
The display layer exposes an API for rendering PDFs and retrieving document information. · mozilla.github.io, 7 Oct 2026
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. · github.com, 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. · github.com, 7 Oct 2026
Distribution
Prebuilt builds are available, and the project lists jsDelivr, cdnjs, and unpkg as CDNs hosting PDF.js. · mozilla.github.io, 7 Oct 2026
Form filling
Yes · mozilla.github.io, 24 Sept 2026
Free plan
Yes · mozilla.github.io, 24 Sept 2026
Integrations
PDF.js is built into Firefox 19 and later, and the project provides a Chromium browser extension. · github.com, 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. · github.com, 7 Oct 2026
Large documents
The FAQ recommends rendering only visible pages to reduce memory use when working with many high-resolution pages. · github.com, 7 Oct 2026
License
PDF.js is licensed under Apache 2.0, and its documentation is licensed under CC BY-SA 2.5. · mozilla.github.io, 7 Oct 2026
OCR support
none · mozilla.github.io, 24 Sept 2026
Platform support
web · mozilla.github.io, 24 Sept 2026
Purpose
PDF.js is a web standards-based platform for parsing and rendering PDF files. · mozilla.github.io, 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. · github.com, 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. · mozilla.github.io, 7 Oct 2026
Support
The project points users to GitHub issues for technical problems and its Matrix room for questions or guidance. · github.com, 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. · mozilla.github.io, 7 Oct 2026

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