Frequently Asked Questions

  • Is Winforms / WPF supported?
    No, the viewer works for Asp.Net only, supports .NET Framework 4.0+ 
    .NET Standard 2.0+. However using a Distribution license you can export
    a document to Pdf within a Winform / Console App / Webservice.
  • Does it work with Asp.Net MVC / Razor?
    Yes, Asp.Net MVC document viewer.
  • Does it work with Asp.Net Webforms?
    Yes, Asp.Net document viewer.
  • Does it work with .net core / .net 6.0+?
    Yes, .Net core document viewer.
  • Does it work with Blazor?
    Yes, Blazor document viewer.
  • Does it work with SharePoint?
    Yes, it does.
  • Does it work with Cloud providers?
    Yes, Amazon AWS S3, Azure Storage, Google Cloud, DropBox, Redis.
  • Does it work with Angular, React, Vue?
    Yes, but there is no sample code for React & Vue. You can refer the Angular sample.
  • Can I view documents from mobile?
    Yes, but please note that you can do this via a mobile browser, not as a native app.
  • Which devices & browsers are supported?
    IE 8.0 and above. Rest all modern desktop and mobile browsers. However we do encourage 
    to check our online demo links from your set of required devices & browsers.
  • Which file formats are supported?
    Asp.Net, MVC, .NET Core:

    HTML & DICOM are not directly available with .NET Core. You can export to PDF and then view.
    You can also try your own file.
  • Do I need office or any other software on server / client?
    No, you will not need to install anything on server or client side. Except any special fonts used.
  • Can I use it inside a Microservice / Webservice, Windows Forms or Console App / Command line?
    Yes, it can be used for PDF conversion i.e. export. However it requires a Distribution license.
  • Are open office formats supported?
    Yes, ODT, ODS and ODP.
  • Can I select and copy text from the document?
    Yes, please download the free PdfJs pdf document viewer from Download page.
  • Can I view files from intranet or an ip address?
    Yes, you can.
  • I am not sure of my production domain name?
    We will issue a temporary license to you, till you decide your final domain name.
  • Can I view file from stream/binary/database?
    Yes, you can view from a physical path, stream or from an url.
  • Do my files go out? Are there any callback to your servers?
    No, your files / information are secured inside your premises and there are no calls
    are made to our servers at any point.
  • Can I edit files and save them back?
    No, our product is a viewer. However you can add annotation and save them to PDF.
  • Are links inside documents clickable?
    Yes, the Pdf format does support clickable links. Word and other formats can be converted to pdf.
    Refer samples and documentation for more details
  • Which languages are supported in search?
    Dutch, English, French, German, Italian, Portuguese and Spanish.
  • What support & updates do I get?
    We provide email support (24 hours turn-around time) and free product updates for 1 year.
    You can however extend this. We do not provide phone or priority support.
  • Are there samples and documentation?
    Yes, there are many samples to get you started and a detailed pdf manual and an integration guide.

  • Licensing

  • Do you allow license upgrading?
    Yes, you can upgrade your license or add plugins at any later date.
  • Does Professional license work from subdomains?
    Yes, it does. However once issued you can't transfer license to another domain.
  • Can I use iFrames with Professional license?
    No, it won't work. License for does not allow any page on with an iframe
    pointing to You need an Enterprise license for this.
  • How do Enterprise and Distribution license differ?
    Enterprise license can't be distributed or used outside your company.
    The domains where it is used should be owned by your company.

    Distribution license can be used within your website/product that are distributed to
    multiple clients. For more details please refer the Buy Now page.
  • Does the license expire?
    No, All licenses are perpetual. You can continue using the software even after the
    free upgrades period expires.
  • How many developers and end users are allowed?
    We have kept our licensing model very simple. The license does not limit
    how many developers or end users can use the control at design-time or run-time.
  • If I buy Professional license will it work on my test/staging server?
    Yes, it will but in watermark mode.
  • Can I get a license issued to an IP or a PC name?
    Yes, you can.
  • Do I need a separate license for .NET Core?
    No, the same license works for Webforms, MVC & .Net Core.
  • I can buy a license just for .DOC or .PDF?
    No, we do not offer license based on file formats.
  • Is the plugin fee paid yearly?
    No, annotation, search, dicom etc are one time fees. And are same for every
    license type.
  • Is it mandatory to upgrade each year?
    No, however if upgrade is not done for 2 or more years then you need
    to pay for previous one year and the coming year.

  • File Format Specific

  • Are animations, embedded videos supported for PowerPoint files?
  • Can I fill PDF Forms?
  • Can I view a large excel file in single page?
    No. For large excel use SplitWorksheets as true in config.
    You may also refer custom Excel viewer sample.
  • Are 3D objects supported for CAD?
    Yes. Use DefaultRender as false in config.
  • Are Excel 95 files supported?
  • Can I view RAW image formats like CR2, NEF, HEIF, HEIC etc.?
    Yes. You can convert them to JPG or PNG, using Magick.NET and then view.

  • General

  • Do you offer any re-seller or partner/affiliate program?
  • I have few questions, can you call me urgently or skype?
    No. Please email us your questions.
  • Do you offer discounts or special pricing for academic/non-profit organizations?
    Yes. Please email us.

  • Technical

  • How can I increase the viewing speed?
    You can change the ImageResolution to lower values (150, 100 or less; default is 200).
    There is a trade off between quality and speed. You can set AutoLoadPages to true,
    then the control will load pages beforehand. Another option for frequently viewed files,
    is to export them to .DCN (see viewer.aspx sample) and then view the .DCN instead
    of the original file.
  • How can I decrease memory usage?
    Please refer AutoClose, TimeOut properties of the control and the WebFarm samples.
  • I am not able to view documents
    Please make sure you have kept the license file in "bin" folder. Next set the DebugMode
    property to true and then reload your page.
  • Original document pages and look is not preserved when viewing
    Please make sure you have all the fonts used by your document installed on the server.
    The viewer will not be able to match the original document 100%.
  • I get "Missing document instance" error on pages
    Please check if there is a load balancer or a web farm set up with multiple worker processes?
    In that case you need to refer the WebFarm sample solution.
    You may also check the timeout of IIS worker process, it is default 20 minutes. You can make it 0, never timeout.
  • I get "Init error: no data from server" error alert
    Please check if you have the handler defined in web.config or is the middleware added in Startup.cs?
    Refer the Integration Guide provided in the documentation folder.
  • I get "The type initializer for threw an exception in Docker/Linux
    Please ensure that you have installed all nugets like SkiaSharp etc. as mentioned in our Docker sample.
  • Trial limitation: Please run / function will work after 'N' seconds,
    when the system clock reads even minutes!
    This is a limitation of trial license. As the error suggests, call the routine when system clock reads even minutes.
    eg. 2:12, 4:20 and not 2:31 or 5:15.
  • Dicom file does not open
    Please make sure the plug-in DLLs are present in bin folder. Then change the IIS application
    pool settings to allow 32 bit applications. Also VC++ Redist should be installed on server.
  • Images missing when viewing Word / Pdf documents
    Please install this specific version of SkiaSharp (2.80.3) from nuget
    and for linux/docker install SkiaSharp.NativeAssets.Linux.NoDependencies (2.80.3).
  • I get an error: Failed To Resolve LoadLibrary
    Change the IIS application pool settings to allow 32 bit applications.
  • I can't open a file. Get Read/IO error.
    You can try opening file from your own code as byte[] and pass it on to Doconut.
    byte[] fileBytes = File.ReadAllBytes(path);
  • Does it work with Telerik and other UI Suites?
    Yes it does, please refer our Ajax Document Viewer sample to get tips.

Not Answered?

Please email us your question in detail and we will get back to you ASAP!