Accessibility Checker for Google Suite Documents - How to Use Grackle


Creating accessible content supports learner variability and provides access to individuals with disabilities. Virginia Tech recommends our community members check the accessibility of teaching materials to make sure they comply with VT Policy 7215 and Section 508 of the Rehabilitation Act.

Grackle is an accessibility checker for Google Workspace applications. Use Grackle to:



How Grackle works

Grackle is a Google Workspace add-on that scans your Google Doc, Sheet, or Slide for accessibility. To scan a document, launch Grackle from within the document. Grackle categorizes accessibility results by document component, for example headings in a Google Doc or Sheets in a Google Sheet. Each category will list elements that are evaluated for accessibility. For inaccessible elements, Grackle details the problem and suggests changes. After you make the changes, share the Google document with students or use Grackle to export it as document as an accessible PDF you can post on Canvas. 

Top of page

Scanning a Document

  1. Log into Your Virginia Tech Google account. 
    1. Go to, click Sign in, and enter your VT email address. 
    2. Sign in with your PID and PID passphrase. 
  2. Open a Google Doc (or Slide or Sheet; it works the same way).
  3. On the toolbar, click Extensions  Grackle Docs  Launch. 
    Image of the above instructions
  4. Click OK.Image of the above instructions
  5. You may be asked to sign into your Virginia Tech Google account again.
  6. Click Allow for Grackle to run in your Google Doc.
  7. Grackle will scan your document for accessibility. 

Top of page

Viewing Scan Results

Scan categories

After scanning a document, Grackle will categorize accessibility feedback depending on the document type and component. 

These instructions are for Grackle Docs, but they also apply to Grackle Sheets and Slides.

Feedback Types

Feedback is marked by category as:

Top of page

Making Corrections

General Procedure
  1. Go to any category with elements that are not accessible or not completely accessible, shown by a red circle. 
  2. Click a problematic element to show details about its accessibility.
    Image problem and description
  3. Click Locate to go to the content in the document, which will be highlighted. Make suggested corrections. 
  4. Click Re-Check at the top of the Grackle ribbon to scan the document again. 
    Re-check circled under Accessibility check tab
Add Image Descriptions (Alt Text)

The most common accessibility problem is a lack of equivalent written content for images. Image descriptions are read aloud for those with visual impairments and are displayed when a slow connection prevents an image from loading. Alt Text should be: 

Engage the reader: 

Accommodate screen readers. Screen readers read aloud on-screen content and Alt Text for images. Be sure to: 

Add Alt Text
  1. In Grackle’s scan feedback Images category, click Images should have alternative text or mark as artifact.
    Image of the above instructions
  2. Click Locate +Tag to go to the image.
    Alt text problem notification expanded
  3. Type in an image description and click Update.
    • You do not need Alt Text for decorative images, logos, and graphic elements. Instead, click Mark as artifact
      Tag image pop-up
  4. Repeat for all images and re-scan to check your work. 
Change the Reading Order

Text-to-speech and screen reading software may not read on-screen content in the same order as it appears visually. You can use Grackle to check and adjust your documents' reading order. 

  1. In Grackle Docs, click Document Structure. (In Grackle Sheets, click Table Structure; in Grackle Slides, click Slides Structure).
    Document structure tab open
  2. The document's reading order will appear, with accessibility feedback highlighted in red.
    Image of the above instructions
  3. Drag and drop a heading to rearrange their reading order. Doing so does not change the document, only how a screen reader reads it aloud. 

Top of page

Exporting Documents as Accessible PDFs

Export learning materials as easily shared, accessible PDF files. 

  1. Scan your document and make suggested changes. 
  2. In Grackle, under Accessibility Check, click Export to PDF.
    Export to PDF circled in Accessibility check tab
  3. If some of the content does not pass the accessibility check, you will be asked if you still want to export.
    • Click Yes to export to PDF.
    • Click No to continue editing.
      confirmation pop-up
  4. Click Start and watch the export progress in the Progress Monitor. 
    Image of the above instructions
  5. When the Progress Monitor says Ready, you can View or Download your PDF.
    Finished progress monitor pop-up

Top of page


Top of page

Getting Help

Top of page