Isaac Maw
Technical Content Creator
Published July 08, 2026
Updated July 08, 2026
5 min
Secure React PDF Viewing: Apryse WebViewer vs PDF.js
Isaac Maw
Technical Content Creator
Summary: Compare Apryse WebViewer and PDF.js for React PDF viewing. Learn the differences in rendering, security, customization, performance, file format support, and enterprise features. Discover when open-source PDF.js is sufficient and when a commercial PDF SDK like Apryse delivers faster development, stronger security, and a more scalable document platform.
The choice of a PDF viewer is a critical architectural decision for developers. It not only impacts user experience, but also time to market, security, and developer workload.
For many new software projects, an open-source solution like PDF.js is the first choice. It’s free and easy to work with, helping teams keep costs low while getting basic functionality off the ground fast. However, at Apryse, we’ve seen that for many teams, as projects grow and mature, PDF.js starts to tick fewer and fewer boxes for capabilities, developer experience, maintenance, scalability, and security. While PDF.js is the common open-source starting point, Apryse WebViewer offers a comprehensive, enterprise-ready upgrade that sets React applications up for ongoing success into the future.
In this article, we’ll look at why so many teams upgrade to Apryse.
Understanding the Foundations: What is PDF.js?
PDF.js is an open-source PDF rendering engine developed and maintained by Mozilla. (Yes, it’s the engine that powers the PDF viewer in Mozilla Firefox). Developers mainly use PDF.js to parse and render PDF files in React applications, and the main benefits are simple: it’s free, open-source, and widely adopted for basic viewing needs.
However, PDF.js has a few key limitations for production applications.
First, it’s primarily a rendering engine, not a full-featured viewing component. Developers must build or source a UI if something more complex is required than the basic UI provided. (PDF.js Express by Apryse offers one way to tackle this, building PDF.js into a full-featured out of the box SDK).
PDF.js can struggle with rendering complex or large PDFs, sometimes leading to inaccurate text layers, incorrect shading, or poor performance. On its own, it also lacks out-of-the box support for advanced features that developers need in React apps. When PDF.js is the solution of choice, these additional features must be built and maintained by the developer.
The Enterprise Alternative: What is Apryse WebViewer?
Apryse WebViewer is a client-side JavaScript SDK for embedding advanced document processing capabilities into web applications. WebViewer isn’t built on a forked open-source engine. It uses Apryse’s own proprietary, high-fidelity rendering engine built with WebAssembly. WebViewer does not use PDF.js.
For enterprise developers, WebViewer provides:
- Comprehensive: support for viewing, annotating, and editing and more across 30 file formats, including PDF, DOCX, Spreadsheets, PPTX, images and CAD files, all client-side within the browser.
- Secure: As an SDK, WebViewer has no external dependencies. Apryse also maintains a commitment to security compliance with certifications to protect your data. Finally, processing documents client-side also provides security compliance benefits for developers, with sensitive documents never leaving the user’s browser.
- Robust and Customizable: Unlike PDF.js, WebViewer comes with a feature-rich, open-source UI that developers can customize to meet specific application requirements such as using brand colors or removing certain buttons. The UI is WCAG 2.2 AA compliant out of the box.
Feature-by-Feature: A Head-to-Head Comparison
In this brief table, you can see how Apryse measures up to PDF.js. While Apryse offers a full suite of document processing capabilities, PDF.js is limited to basic rendering. In addition, Apryse handles security compliance, and supports more file types beyond PDF.
Feature | PDF.js | Apryse WebViewer |
|---|---|---|
Rendering Engine | Open-source, canvas-based | Proprietary, high-fidelity WebAssembly engine |
UI Components | Basic OOTB UI | Extensive UI, source available, and fully customizable (React-based) |
Annotations | 5 annotation tools out-of-the-box | 35+ annotation tools out-of-the-box, collaboration features |
Form Filling | Basic support | Advanced form filling, creation, and data extraction |
Digital Signatures | Basic e-signature drawing tool | Full cryptographic digital signature workflow (creation, validation, LTV, PAdES) |
True Redaction | Not supported | Securely and permanently remove sensitive data |
File Support | PDF only | PDF, DOCX, XLSX, PPTX, CAD, images, & more |
Security Model | Client-side processing | Client-side processing, SOC 2 Type II, annual independent penetration testing |
Accessibility | Developer's responsibility | WCAG 2.2 Level AA compliant out-of-the-box |
Enterprise Support | Community-based | Dedicated technical support from document processing experts |
Licensing | Apache-2.0 (Free) | Commercial license with a free trial |
Security Deep Dive: Why Client-Side Processing Matters
Security is a key differentiator in this comparison between Apryse WebViewer and PDF.js. While security may not matter for prototypes and early adopters, it’s essential for enterprise software that must stand up to rigorous vendor evaluations and handle sensitive documents.
Apryse WebViewer: A Zero-Trust Approach
We understand that our customers rely on Apryse to handle sensitive information and our products are integrated into important parts of your infrastructure. That’s why we’ve implemented rigorous security practices and controls to ensure the confidentiality, integrity, and availability of our systems and services. Apryse has achieved the following certifications and attestations:
- ISO/IEC 27001:2022 Certified
Our Information Security Management System (ISMS) is certified to the ISO/IEC 27001:2022 standard, reflecting our systematic approach to managing sensitive company and customer information. We have held certifications since 2018. - SOC 2 Attested
We have successfully completed yearly SOC 2 Type II audits, verifying that our controls continue to meet the Trust Services Criteria for security, availability, and confidentiality.
For data security compliance, where data is located is important. With API services, for example, while hyperscale vendors such as Microsoft, Google and Amazon maintain robust security compliance certifications, data is still processed on the third-party server. This may cause compliance issues in highly regulated industries.
By comparison, with WebViewer, all documents are processed client-side. This means that document data is never transmitted to an external server, enabling deployment of WebViewer in secure environments, including on-premise, private cloud, or even air-gapped networks.
Another important aspect is document security itself. Even if the architecture and SDK is secure, document processing capabilities can lead to security incidents by way of issues like incorrect redaction, unencrypted documents, and unsecured documents falling into the wrong hands. Apryse supports several document security features, including:
- Custom Encryption: Create or remove any document security settings with your own custom encryption algorithm that supports industry standard PDF security with RC4 and AES.
- Watermarks: Securely embed static or dynamic watermarks with names, dates, and custom content into your documents.
- Permissions Control: Implement multi-level password protection and secure document access to prevent users from making unauthorized changes.
- Secure Redaction: Apply redaction annotations for review, then permanently remove redacted data from the document.
Security Considerations with PDF.js
PDF.js itself isn’t insecure. However, the security issue developers face with PDF.js is that the responsibility for securing the entire document workflow falls on the developer. This requires time and resources that neither startups nor enterprise software teams have to spare. In addition, advanced document security features like watermarks, redaction and permissions require custom development or additional libraries, and all the maintenance, risk and dependencies that go along with them.
Integration in React: A Practical Walkthrough
Let’s take a look at what it takes to add WebViewer to a React App vs. PDF.js to help illustrate the difference in developer ease of use.
Adding WebViewer to a React App
Most developers add WebViewer to react using Vite and npm. You can get started with our Github Sample webviewer-react, and check out these quick instructions for a better understanding. Before you begin, you’ll need:
- Node.js and npm to install Vite and WebViewer
- Your code editor, such as Visual Studio Code or whatever you use
- Your free Apryse trial key
Once that’s ready, you’ll follow these simple steps detailed in our tutorial to integrate WebViewer into a new React app.
- Create and set up a React project
- Install WebViewer using npm:
npm i @pdftron/webviewer - Copy WebViewer assets into the public directory
- Instantiate the WebViewer SDK to create the PDF Viewer in your app
- Verify your output in localhost using:
npm run dev These simple steps give you a fully functional viewer with a complete UI. You can also check it out on our Showcase demo site.
Building a Viewer with PDF.js in React
To build with PDF.js in React, you could use a library like React PDF. Here’s what the developer effort required might look like to get up and running with this open-source library. You can check out a detailed version of these instructions in our blog, How to Build a React PDF Viewer with PDF.js. You’ll need Node.js for this, as well.
- Create and set up your React project
- Set up a backend class for PDF rendering that you can reference elsewhere in your React component
- Download PDF.js and extract it to the public directory
- Build an iframe to implement PDF.js UI
5. Verify your output in localhost
Choosing the Right Viewer for Your React Application
Aprys offers a complete document SDK solution that supports developers not only as they quickly stand up PDF viewers, but also as application requirements scale into additional features such as digital signatures, PDF editing, and MS Office support. In addition to WebViewer, Apryse also offers the Server, Mobile and Scanbot SDKs to support the end-to-end workflow, from document intake to OCR, data extraction and archiving.
For developers making the decision between PDF.js and a commercial enterprise-grade SDK like Apryse, here are the basic things to consider:
Consider PDF.js when:
- The document portion of the project is simple in scope, and only basic, read-only PDF display is needed.
- Budget is zero, and developer time to build and maintain a custom solution is abundant.
Consider Apryse WebViewer when:
- PDF capabilities are part of mission-critical workflows, where reliability and security are non-negotiable.
- You need or will grow into features beyond viewing, such as annotation, MS Office editing, form creation, or redaction.
- Fast time-to-market is crucial, and you want to avoid the engineering overhead of building a viewer from scratch.
- You require professional, dedicated support to resolve issues quickly.
Conclusion
While PDF.js is a great low-cost option for PDF rendering, Apryse WebViewer is a complete, secure and supported document processing SDK. For developers, the choice boils down to an investment in custom development effort and ongoing maintenance versus a robust, scalable document platform at the cost of the commercial license.
To see the difference for yourself, get your trial key and start using WebViewer in your React application, or browse the WebViewer documentation to learn more.
