# Pdfjs-express vs webviewer license key

**URL:** <https://pdfjs.community/t/pdfjs-express-vs-webviewer-license-key/1735>\
**Category:** Technical Support\
**Tags:** pdfjs-express\
**Created:** [June 2, 2022, 3:44pm UTC](https://pdfjs.community/t/pdfjs-express-vs-webviewer-license-key/1735 "2022-06-02T15:44:37Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/ffbcd25c7d423db8d5acd5db201c272f4db306dd.png) [@system](https://pdfjs.community/u/system)\
**Post date:** [June 2, 2022, 3:44pm UTC](https://pdfjs.community/t/pdfjs-express-vs-webviewer-license-key/1735/3 "2022-06-02T15:44:43Z")

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**Hello, I’m Ron, an automated tech support bot 🤖**

While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:

Guides:
- [Migrating from PDF.js Express to PDFTron - 3. Change initiation](https://pdfjs.express/documentation/learn-more/pdfjs-express-to-pdftron.8#3.-change-initiation)
- [PDF.js Express Viewer Overview - What is PDF.js Express Viewer?](https://pdfjs.express/documentation/get-started-viewer#what-is-pdf.js-express-viewer?)
- [Adding your license key - PDF.js Express Plus License Keys](https://pdfjs.express/documentation/get-started/add-license-key#pdf.js-express-plus-license-keys-<span-class='plus'></span>)

APIs:
- [PDF.js Express Utilities](https://pdfjs.express/api/utils/index.html#__anchor)
- [ExpressUtils(optionsopt) - # async watermark(options) → {Promise.}](https://pdfjs.express/api/utils/ExpressUtils.html#watermark__anchor)
- [UndefinedWebViewer(options, viewerElement)](https://pdfjs.express/api/global.html#WebViewer__anchor)

Forums:
- [Can I remove pdfjs.express watermark from viewer?](https://pdfjs.community/t/can-i-remove-pdfjs-express-watermark-from-viewer/1073/4)
- [Is there any way to remove watermarks in development mode?](https://pdfjs.community/t/is-there-any-way-to-remove-watermarks-in-development-mode/443/1)
- [Cannot remove watermark, even with license information](https://pdfjs.community/t/cannot-remove-watermark-even-with-license-information/1125/1)

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