# PDF file download progress callback

**URL:** https://pdfjs.community/t/pdf-file-download-progress-callback/1207
**Category:** Technical Support
**Tags:** pdfjs-express
**Created:** [November 30, 2021, 3:57pm UTC](https://pdfjs.community/t/pdf-file-download-progress-callback/1207 "2021-11-30T15:57:25Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![user13](https://avatars.discourse-cdn.com/v4/letter/u/a88e57/32.png) [@user13](https://pdfjs.community/u/user13)
#### Post date: [December 2, 2021, 10:43am UTC](https://pdfjs.community/t/pdf-file-download-progress-callback/1207/5 "2021-12-02T10:43:48Z")

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Thx for the reply

I am talking about the server side, not the client providing their own PDF.

Range requests are supported by the server, but somehow pdfjs express does not execute them (it downloads the whole file in one go). I tested by swapping pdfjs-express on our web app and replacing it with PDFTron, and that one does perform range requests.

Does [pdfjs.express](http://pdfjs.express) support range requests, or is this feature reserved for the paid versions of the libraries? I am using “@pdftron/pdfjs-express-viewer”: “8.1.1”. Thx

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