Is it possible to speed up the load time of a large PDF file? (5MB)

PDF.js Express Version


Detailed description of issue
A client has complained that one of their PDFs (a single page colored construction drawing 5MB PDF) takes a long time to load. The annotations load almost immediately, but the PDF itself takes about 35 seconds to load.

Does your issue happen with every document, or just one?
As far as I’m aware, this is the first that’s taken this long to load the first page. (It’s a single page, granted, but takes 35 second to load that first page).

Is there anything that can be done to speed up this load time? If not with the WebViewer itself, maybe by asking the client to save (linearize?) the PDF in another compressed format?

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Some files can definitely take longer to render for many different reasons. Linearization only really helps for multi page documents.

Are you able to send me the document in question?



Can I send it to your email? I don’t want to post it publicly here.



Hey Lucas,

Thank you for sending the document.

I tested it out in a bunch of viewers and this document is slow everywhere. Even desktop readers like Adobe Acrobat on a pretty powerful computer take a while to render it.

I tried running the document through some flattening / compression software to see if it helped, but I could not find a tool that could handle that file without throwing some kind of out of memory error.

This is just a very heavy, complex document so unfortunately there is not a lot I can do here on my end.


Hey Logan,

That’s what I suspected but wanted to make sure.

Thanks for looking into this.


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