PDF.js Alternative
PDF.js is Mozilla's open-source PDF viewer. It's free, widely used, and the default PDF renderer in Firefox. Every developer's first instinct is to reach for PDF.js because it's battle-tested and has zero vendor lock-in. Then they discover it's a viewer: no text input, no signatures, no form submission, no webhooks. Teams often spend weeks building editing features on top of it and end up with a fragile custom solution.
What you get with SimplePDF
Editing out of the box
Text input, signatures, checkboxes, images, and form field auto-detection. Everything you'd have to build yourself on top of PDF.js.
One line of code
A single iframe embed. No npm packages, no build steps, no custom UI layer to maintain.
Form submission built in
Users fill the PDF and submit. You receive the completed document via webhook, with optional BYOS (S3, Azure) for direct storage. PDF.js has no submission concept.
White-label ready
Your brand, your domain. The editor looks like part of your product. No SimplePDF branding unless you want it.
Feature Comparison
| Feature | PDF.js | SimplePDF |
|---|---|---|
| View PDFs | Yes | Yes |
| Add text | No | Yes |
| Add signatures | No | Yes |
| Fill form fields | Interactive fields only | Interactive + auto-detected |
| Submit filled forms | No | Webhook + optional BYOS |
| Add images | No | Yes |
| Add checkboxes | No | Yes |
| White-label | Yes (your own UI) | Yes (built-in) |
| BYOS (S3, Azure) | N/A | Yes |
| Client-side processing | Yes | Yes (in-browser) |
| Integration effort | Days to weeks (custom UI) | Minutes (one iframe) |
| Pricing | Free (open-source) | Free tier / $99/mo |
Integration Comparison
npm install pdfjs-dist
import * from 'pdfjs-dist';
const pdf = await getDocument('doc.pdf');
const page = await pdf.getPage(1);
const viewport = page.getViewport({ scale: 1 });
const canvas = document.createElement('canvas');
page.render({ canvasContext: ctx, viewport });
// Then: build custom toolbar,
// text input layer, signature pad,
// form field detection, submission...<iframe
src="https://yourcompany.simplepdf.com/editor"
width="100%"
height="800px"
/>Where PDF.js is the better fit
- You need full rendering control and want to customise every pixel of the viewer UI
- You need a free, open-source solution with no vendor dependency
- You only need viewing, not editing or form filling
- You want to build a specialised PDF tool and need low-level access to the rendering pipeline
- Offline-first requirements where no external service calls are acceptable
Which SimplePDF product fits?
Embed
For developers who would otherwise build on PDF.js. One iframe gives you the full editing experience without maintaining a custom UI layer.
Learn about EmbedPortal
For non-technical teams who need to collect filled PDFs from users. Create a shareable link, users fill the PDF in their browser, you get the completed document.
Learn about PortalGot any questions?
Can I edit PDFs with PDF.js?
PDF.js is a viewer, not an editor. It can render PDFs and handle interactive form fields (fields that are already built into the PDF), but it cannot add text, signatures, images, or checkboxes to a PDF. To add editing capabilities, you would need to build a custom layer on top of PDF.js.
How do I add form filling to PDF.js?
PDF.js supports filling interactive AcroForm fields natively. For non-interactive PDFs (scanned forms, flat PDFs), you need to build a custom annotation layer. SimplePDF handles both interactive and non-interactive forms with auto-detection, requiring no custom code.
Is there a free PDF editor like PDF.js?
SimplePDF has a free tier that includes viewing, editing, and form filling. Unlike PDF.js, which is a viewer you extend yourself, SimplePDF provides a complete editing experience out of the box. The free tier has no watermarks, no sign-up required, and no ads.
PDF.js vs an embeddable PDF editor: which should I use?
If you only need to display PDFs and are comfortable building your own UI, PDF.js is a solid choice. If you need users to edit, fill, sign, or submit PDFs, an embeddable editor like SimplePDF saves weeks of development. The trade-off is vendor dependency vs. development time.