# Pdf.js Express Viewer license expriation

**URL:** <https://pdfjs.community/t/pdf-js-express-viewer-license-expriation/1668>\
**Category:** Technical Support\
**Created:** [May 10, 2022, 5:26pm UTC](https://pdfjs.community/t/pdf-js-express-viewer-license-expriation/1668 "2022-05-10T17:26:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![quenten.vanegeren](https://avatars.discourse-cdn.com/v4/letter/q/5f9b8f/32.png) [@quenten.vanegeren](https://pdfjs.community/u/quenten.vanegeren)\
**Post date:** [May 10, 2022, 5:26pm UTC](https://pdfjs.community/t/pdf-js-express-viewer-license-expriation/1668/1 "2022-05-10T17:26:53Z")

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I have a question about the license keys for the Pdf.js Express Viewer.  
I realize this license is free, but will it ever expire and change for a given domain?

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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:** [May 10, 2022, 5:26pm UTC](https://pdfjs.community/t/pdf-js-express-viewer-license-expriation/1668/3 "2022-05-10T17:26:58Z")

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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:
- [Integrating PDF.js Express Viewer into a Vue.js project - Prerequisites](https://pdfjs.express/documentation/get-started-viewer/vue#prerequisites)
- [Integrating PDF.js Express Viewer into a new Blazor project - Prerequisites](https://pdfjs.express/documentation/get-started-viewer/blazor/new-project#prerequisites)
- [Integrating PDF.js Express Viewer into an existing Blazor project - Prerequisites](https://pdfjs.express/documentation/get-started-viewer/blazor/exist-project#prerequisites)

APIs:
- [PDF.js Express Utilities](https://pdfjs.express/api/utils/index.html#__anchor)
- [Core - preloadPDFWorker(pdfBackendType, workerHandlers)](https://pdfjs.express/api/Core.html#.preloadPDFWorker__anchor)
- [ExpressUtils(optionsopt) - # async set() → {Promise.}](https://pdfjs.express/api/utils/ExpressUtils.html#set__anchor)

Forums:
- [Licensing problem in a intranet environmnet](https://pdfjs.community/t/licensing-problem-in-a-intranet-environmnet/1116/1)
- [Pdfjs.express 8.2.1 error on a valid License Key](https://pdfjs.community/t/pdfjs-express-8-2-1-error-on-a-valid-license-key/1340/1)
- [Can I remove pdfjs.express watermark from viewer?](https://pdfjs.community/t/can-i-remove-pdfjs-express-watermark-from-viewer/1073/4)

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**Author:** ![Logan](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/logan/32/13_2.png) [@Logan](https://pdfjs.community/u/Logan)\
**Post date:** [May 11, 2022, 3:28pm UTC](https://pdfjs.community/t/pdf-js-express-viewer-license-expriation/1668/4 "2022-05-11T15:28:35Z")

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Hey there,

Nope, the license will never expire - nothing to worry about. If something does need to change we will give you plenty of notice.

Thanks,  
Logan