Dev Center
Table of contents

Thanks for Downloading Dynamic Web TWAIN 30-Day Trial!

Your download will start shortly. If your download does not begin, click here to retry.


SDK Download/Free Trial

  1. How can I extend my free trial?
  2. Where can I download an older version of the Dynamic Web TWAIN SDK?
  3. Do you provide free trial versions of the Dynamic Web TWAIN SDK?
  4. Can I run the scanning service on an ARM-based embedded device, such as Raspberry Pi?
  5. Do you also provide an SDK download for Linux and Mac developers?
  6. Is the free trial version fully functional?
  7. Can I use the Dynamic Web TWAIN SDK to create a PWA application?

Capture/Image Source

  1. Download virtual scanner for testing
  2. What physical document scanners does the Dynamic Web TWAIN SDK support?
  3. How to use TWACKER to check if your device is TWAIN Compliant?
  4. How to test if your scanner supports ICA scanning on Mac OS?
  5. How to test if your device is SANE compliant?
  6. How to test if your camera is DirectShow compliant?
  7. How to test if your camera is MediaDevices compliant?
  8. Can I set scanning settings without using the default scanner's UI? What pre-scanning settings do you support?
  9. Can I hide offline scanner devices from the select source list?
  10. Can I hide webcam devices from the select source list?
  11. What are the differences between TWAIN and WIA?
  12. How to exclude WIA sources in the source list?
  13. How can I set the last selected source as the default source for an end user?
  14. How can I limit all users to use a specific scanner model?
  15. Can the Dynamic Web TWAIN SDK automatically remove blank pages during the document scanning process?
  16. Can the Dynamic Web TWAIN SDK automatically rotate upside-down pages during the document scanning process?
  17. Can the Dynamic Web TWAIN SDK automatically detect borders of the scanned document and crop it out?
  18. Can I set my document scanner to scan x number of pages instead of all pages from the automatic document feeder (ADF)?
  19. Can the Dynamic Web TWAIN SDK detect whether papers exist on the flatbed?
  20. How can I get a list of supported resolution/DPI values from the document scanner?
  21. How can I use a custom capability of my scanner hardware when there is no direct API to set it?
  22. Is there a limit on the number of pages I can scan at a time? Where do you store them after scanning?
  23. Document scanning via the Dynamic Web TWAIN SDK is slower than using the native scanner application. How can I speed it up?
  24. Can I use built-in or USB webcam to capture document?
  25. Can I import existing images or PDF documents using the Dynamic Web TWAIN SDK?
  26. Can I download an image from a FTP or HTTP server using the Dynamic Web TWAIN SDK?
  27. How can I trigger an automatic workflow right after document scanning or image importing?
  28. Do you support capturing documents from mobile camera?
  29. Do you support fingerprint or medical imaging devices?
  30. What is the earliest iPhone model that your SDK supports?
  31. Is the AcquireImage() method synchronous or asynchronous?
  32. Why is my scanner not shown or not responding in the browser?
  33. How can I support WIA scanner drivers in my application?
  34. Why are my images coming out distorted in MacOS Sonoma?

Image Viewer

  1. Where is the image viewer object defined?
  2. Can the size of the image viewer auto resize when the browser window size changes?
  3. How can I create a thumbnail viewer to view images?
  4. How can I change the background color of the image viewer?
  5. How can I reorder images in the viewer?
  6. How can I disable drag and drop images in the viewer?
  7. How can I show multiple images at a time?
  8. How can I show page number on each image?
  9. How can I resize the view of image (e.g. zoom in/out on an image)?
  10. What mouse click events does the viewer support?
  11. How can I insert an image after a selected image in the viewer?
  12. Can I protect sensitive information of an image from being seen?
  13. Can I hide the Dynamsoft image viewer and use my own image viewer?
  14. Can I print images from the viewer?
  15. How to get the coordinates of the selected area on an image?

Image Editing

  1. What image editing operations does the Dynamic Web TWAIN SDK support?
  2. How can I show the default image editor tool?
  3. Do you support image deskew?
  4. How can I resize all images to meet a certain size standard (e.g. A4 size)
  5. Can I add annotation to an image (e.g. add watermark or text)?
  6. Can I change the resolution/DPI of an image in the viewer?
  7. Can I convert a color image to grayscale or black & white?
  8. Is there an undo functionality?
  9. How can I remove only the selected images?

UI Customization

  1. Is the UI of the Dynamic Web TWAIN SDK fully customizable? What cannot be customized?
  2. How can I change the display language of all messages from English to another language?
  3. How can I change/hide the spinner which shows during document scanning?
  4. How can I change/hide the UI of the progress bar when importing or uploading images?
  5. Can I customize UI elements of the built-in image editor?
  6. Can I stop the scanner from showing its default popup when there is a paper jam?
  7. Why I cannot hide the loading bar (spinner)?

Document Saving

  1. What image and document formats can I save my documents as?
  2. What type of HTTP servers do your support? Do you support other server types?
  3. How can I enable HTTPS support?
  4. How can I get the smallest size of documents in PDF, TIFF or JPEG format?
  5. How can I send additional form fields with images to my server or database?
  6. How can I automatically trigger actions when images arrive on my server side?
  7. Can I upload documents to a different website domain?
  8. How can I get a response string from my HTTP Server if the upload succeeds or fails?
  9. Can I upload documents via a background service outside the web browser?
  10. Can I insert newly scanned pages to an existing document?
  11. How can I upload a JSON file to my server?
  12. How can I save selected images instead of all images to my server or database?
  13. How to use a blank page as a separator?
  14. How to upload multiple files at a time?


  1. Where does the Dynamic Web TWAIN SDK store images on end-user machines? Are they encrypted?
  2. Can I prompt the end-user when the Dynamic Web TWAIN SDK attempts to visit any local resources (scanner, camera, or disk drive)?
  3. When are the locally cached images destroyed?
  4. The license key is set in JavaScript. How can I protect it?
  5. Does the Dynamic Web TWAIN SDK use any deprecated technologies like NPAPI or ActiveX?
  6. How can I securely transfer scanned documents to my server?
  7. Can I generate an encrypted file in PDF format?
  8. Can I limit the size of documents to be uploaded to my server?
  9. Is the Dynamic Web TWAIN SDK ISO 27001 compliant?
  10. Is the Dynamic Web TWAIN SDK GDPR compliant?
  11. Is the Dynamic Web TWAIN SDK HIPAA compliant?
  12. How can I change the certificate of the Dynamsoft Service?


  1. Do I need a separate license for each addon?
  2. When do I need PDF Rasterizer Addon? Can I load existing PDF files into the Dynamic Web TWAIN SDK without the PDF Rasterizer addon?
  3. How can I load PDF/A files into the Dynamic Web TWAIN SDK?
  4. Can I load specific page numbers of a PDF file into the viewer?
  5. Do I need the PDF Rasterizer addon to convert scanned documents to PDF files?
  6. How can I generate PDF/A files?
  7. Does your Barcode Reader addon support patch code?
  8. How can I separate my documents automatically by barcode?
  9. Is there any way to speed up the barcode reading process?
  10. What types of webcams does the Webcam Capture addon support
  11. Can I use the WebAssembly Edition of SDK to support webcams instead of using the Webcam Capture addon for Desktop Service Edition?
  12. What is the difference between and Camera.showVideo?
  13. What is the difference between WebTwain.Addon.Camera and WebTwain.Addon.Webcam?

Project Deployment and End-user Installation

  1. What are the Resources files?
  2. What resources of the SDK should be included in my web application?
  3. How can I change the reference path to the Dynamsoft's resources in my project?
  4. How can I enable Remote Scan?
  5. How can I use Dynamic Web TWAIN in a Citrix environment?
  6. Is there any component of the Dynamic Web TWAIN SDK that needs to be installed on end-user machines?
  7. What does the Dynamsoft Service do on the end-user machine?
  8. Are admin right required to install the end-user component?
  9. Can I install Dynamsoft Service silently?
  10. Is there an easy way to deploy the end-user components to all users?
  11. How to uninstall Dynamsoft Service?
  12. I have installed the Dynamsoft Service on an end-user machine but still got asked to install it repeatedly. Why?
  13. Dynamsoft Service installation and uninstallation issue
  14. Can I use two different websites integrated with two different versions of Dynamic Web TWAIN on the same computer?
  15. How do I upgrade my project to use the latest version of the Dynamic Web TWAIN SDK?
  16. How do I upgrade the end-user installation for all end users once I upgrade my project?
  17. How to resolve if Dynamic Web TWAIN stops working on insecure websites in Chrome v94?
  18. How to resolve Dynamic Web TWAIN issue in Chrome 101?
  19. Dynamic Web TWAIN – Content-Security-Policy violated
  20. Scanner source is listed on XSane applicaton but not on my web application on Linux machines
  21. How to run Dynamic Web TWAIN ActiveX in Microsoft Edge Internet Explorer (IE) mode
  22. The scanner's UI or the system's file dialog does not open when scanning
  23. How do I know which SDK version I am using?

Error Troubleshooting

  1. General troubleshooting steps
  2. General failure
  3. A connection with the server could not be established
  4. HTTP request error
  5. HTTP process error
  6. Only 24-bit true color bmp and 8-bit gray-scaled images are supported for JPEG compression
  7. XMLHttpRequest cannot load XXX
  8. Source is connected to the maximum supported number of applications
  9. Sequence error
  10. Request header field dwt-md5 is not allowed by Access-Control-Allow-Headers in preflight response
  11. The handle is in the wrong state for the requested operation
  12. The connection with the server was terminated abnormally
  13. Syntax error – Unexpected Token "<"
  14. Uncaught ReferenceError - DVS is not defined
  15. Error message - The current product key does not support XXX, please contact the site administrator
  16. Error message - The current product key does not support current OS for embed device, please contact the site administrator
  17. Error message - The current product key is empty or invalid, please contact the site administrator
  18. Error message - The current product key is missing the core license, please contact the site administrator
  19. Error message - The domain of your current site does not match the domain bound in the current product key, please contact the site administrator
  20. Error message - The current product key is invalid because it's generated with the licenses of a different major version
  21. Error message - The current product key is not for full/trial version, please contact the site administrator
  22. Error message – The current product key has expired on XXX, please contact the site administrator
  23. Error Message - Failed to load resource: net::ERR_CERT_DATE_INVALID
  24. Error Message - The connection from the insecure (HTTP) web page to the local 'Dynamsoft Service' failed
  25. Error Message - Source has nothing to capture
  26. Warning Message - Canvas2D: Multiple readback operations using getImageData are faster with the willReadFrequently attribute set to true
  27. Error Message - Uncaught TypeError: Cannot read properties of null (reading 'appendChild') or Failed to execute 'appendChild' on 'Node': parameter 1 is not of type 'Node'
  28. Error Message - User cancelled the operation
  29. The loading bar keeps spinning when capture the image with iPhone.

Licensing and Purchase

  1. What's the difference between the Desktop Service Edition and WebAssembly Edition?
  2. Is internet connectivity required to use all licenses?
  3. Does the per-server license allow unlimited number of client devices and end users?
  4. What license should I purchase if I am providing SaaS?
  5. For the per-client-device licensing model, can seats taken by retired/unused devices be released from the license?
  6. Will a client machine take an additional license seat if its operating system is reinstalled?
  7. What if I reach the limit of the granted number of license seats?
  8. Do you offer lifetime/perpetual licenses?
  9. Do I need to purchase a license for my dev or testing environment?
  10. I need to resell the SDK within my application to my customers. What options do you offer?
  11. Are you flexible to discuss custom licensing models?
  12. Do you have any local resellers from whom I can purchase a license of the Dynamic Web TWAIN SDK?
  13. Do I get free upgrade if there is a newer version available?
  14. What is your discount policy?
  15. What's your refund policy?

Is this page helpful?

YesYes NoNo

In this article:

latest version

    • Latest Version (18.4)
    • Version 18.3
    • Version 18.1
    • Version 18.0
    • Version 17.3
    • Version 17.2.1
    • Version 17.1.1
    • Version 17.0
    • Version 16.2
    • Version 16.1.1
    Change +