Substack Accessibility Checklist 2026 | WCAG 2.1 AA for Newsletters & Publications

After uploading or embedding an image, click on it in the editor and look for the alt text or 'ALT' input (sometimes located inline, sometimes in an image properties panel). Write a sentence that conveys what the image communicates: for a chart, describe the trend or data point that matters; for a screenshot, describe the interface and the action depicted; for a meme or illustration, describe the visual and tone. For images that are already in the final Substack HTML without alt text, consider adding a visible caption underneath that describes the image as a fallback.

Reserve Heading 1 for the post title (which Substack assigns automatically). Use Heading 2 for the main sections of your post, and Heading 3 for subsections within those sections. Avoid using bold paragraph text as a heading substitute — screen readers will not announce it as a heading. If your post is naturally short (under 500 words), a heading structure may not be needed at all; do not add headings just to break up text visually, use them only for real structural divisions.

Open your Substack publication settings and locate the brand/theme color options. For each color you have selected, test the button text against the button background using a contrast checker such as WebAIM's. If the ratio is below 4.5:1 for normal-size button text, pick a darker or more saturated variant of your brand color. Verify that hover and focus states also meet the ratio. Consider creating two versions of your brand color: one for large display use and a higher-contrast variant for small text on buttons and labels.

Rewrite link text to describe the destination or the action. Instead of 'you can read more about this study here', write 'you can read the 2026 Pew study on remote work'. Highlight the noun phrase that identifies the destination, not the verb. For cases where the surrounding sentence would become awkward, add an aria-label via a raw HTML block (available on some plans), though restructuring the sentence is usually preferable.

For embedded YouTube or Vimeo videos, confirm that accurate captions are available (either human-authored or carefully corrected auto-generated captions). For your own podcast episodes published through Substack, publish a transcript either in the post body beneath the audio player or as a downloadable document linked from the post. Third-party services like Descript, Otter.ai, or Riverside can generate reasonably accurate transcripts that you can proof and paste in under an hour per hour of audio.

This is largely a platform-level issue that Substack needs to address in their comment component. In the meantime, set expectations with your readers by noting in your publication's About page that comment threads may be harder to follow with assistive technology and invite alternative modes of participation (emailed replies, DM responses). If you rely heavily on community discussion, consider augmenting comments with a more accessible off-platform community such as a Discord server or threaded forum.