In a recent viral photo from the popular Twitter account Bodega Cats, a black cat is peering into the camera from its perch behind a shelf at a corner store. Surrounded by hanging packages of Sour Patch Kids, Haribo gummy bears, and other brightly-colored treats, the cat is invisible except for its two watchful green eyes, narrowed slightly and glaring from the shadows. There’s no text in the post, but the joke is obvious: choose your snack wisely.

The picture has been liked and retweeted thousands of times. But for people using screen readers, as many blind or low vision users do, the content is imperceptible. The person running the account hasn’t added alternative text — or alt text — to the photo.

If the post were retweeted or shared on Katie Durden’s timeline, it would read, simply, “Image.” If it’s a collection of four pictures, that would be, “Image image image image.”

Durden has been blind since the age of four and uses a screen reader to browse Twitter. With no description in the tweet and no alt text added, any humor, delight, or joy would be flattened. Their screen reader would read out the handle of the account, display name, timestamp of the tweet, but nothing else other than the fact that there’s a photo.

“It’s utterly useless to me,” Durden says. “I have no idea what is going on.”

To people who can’t read the internet visually, it’s delivered to them orally. But it’s accessibility features like alt text that allow screen readers to recognize what’s in a picture — from a news outlet debunking fake screenshots of Bill Gates’ account getting suspended, to a scene from a nightclub where a man and a woman smile blissfully unaware, lipstick smeared over both of their faces.

The Alt Text Reader bot is one of several accounts that have popped up in recent years, largely run on a volunteer basis. The accounts work in a variety of ways, from private reminders to public prodding, but they have the same goal: to fill in accessibility gaps on the platform.

Fynn Heintz, a software developer in Berlin, created the Alt Text Reader Twitter bot in 2018 after he saw other users express disappointment that there wasn’t an easy way to identify alt text. Prior to recent updates on Twitter, alt text was difficult to find, even when added by the tweet author.

“You could only access it with a screen reader,” Heintz says. “Or, if you know how to inspect the website, go in the code and look at that.”

When tagged under a tweet, Alt Text Reader Bot pulls whatever alt text has been written for an image and tweets the description in a reply, making it far easier to find. The bot has analyzed over 51,000 tweets in 18 languages, according to Heintz, and Twitter users tag it under everything from memes to county health department charts.

In April, Twitter introduced an alt text badge that appears in the corner of images and GIFs when alt text is added. Anyone can access the alt text by clicking the “ALT” button in the corner, rendering Heintz’s bot somewhat obsolete. But many people still use it, and Heintz intends to maintain it as long as he’s able to.

Megan Lynch, a graduate student at the University of California, Davis, has used Heintz’s bot and others like it to screen images on Twitter to make sure they have alt text before retweeting them, so any followers using a screen reader will be able to understand the tweet.

Accessibility bots are helpful tools to further her larger goals. Lynch is the founder of UC Access Now, a coalition of students, staff, and faculty at the University of California schools fighting to make campuses more accessible to people with disabilities.

Several years ago, Lynch and other organizers began auditing university tweets and webpages and found they were largely inaccessible to people with disabilities. Since then, she’s used the bots to draw attention to important images and notices posted on Twitter without alt text, including affordable housing announcements, National Weather Service storm alerts, and event flyers for panels about disability studies.

“The bots have been very useful to me, because if I just tell people ‘I hardly ever see an NWS account [add alt text],’ they don’t believe me. They think I’m exaggerating,” Lynch says. By tagging the bot on posts lacking alt text, or with poorly written alt text added, Lynch says she’s able to demonstrate publicly how much of Twitter is inaccessible.

Heintz notes that his bot is used for practical purposes, but also to prove a point — some followers use the bot to gently shame accounts that neglect describing images. Screen reader users who don’t need a bot to fetch alt text will sometimes summon it to demonstrate that important parts of a tweet are missing for them.

Hannah Kolbeck, a software engineer based in Portland, took a different approach. Kolbeck’s bot, Alt Text Reminder, sends a private message to followers each time they post an image without alt text. Originally created to serve around 10 people in her immediate Twitter circle, Kolbeck’s bot now serves nearly 20,000 followers, and she maintains it on a volunteer basis.

Alt Text Reminder is for people who have already decided they want to make their timelines more accessible, Kolbeck says. The bot makes carrying out that commitment easier.

“The whole idea is if you forget, I don’t want to shame you,” Kolbeck says. Other bots, while friendly in their responses, still pointed out a lack of alt text through a public reply tweet. “I looked at that and decided that shame wasn’t a good motivator there.”

Reached for comment, Twitter spokesperson Shaokyi Amdo noted internal teams dedicated to accessibility at the company and recent feature rollouts, like the alt text badge and caption features for voice Tweets and in Twitter Spaces.

More can be done on Twitter’s part to make the platform accessible, says Durden, the screen reader user. They’ve worked to educate followers and their community about alt text since joining Twitter in 2020.

“What’s really been most effective for me is teaching as many people as are willing to learn what alt text is, why it’s important, and how they can help me be the squeaky wheel,” Durden says.

Durden, along with other blind users and allies, have long asked Twitter for features like built-in reminders. The ability to edit or add alt text after posting, too, would make it easier for people who want their content to be accessible to do so. The feature is available on Facebook, Durden notes, but not yet on Twitter.

“This is the thing disabled people deal with all the time. I’m asking for what I need, and I’m not getting what I need, so I ask again and again,” they say.

Beyond additional features, Durden and others say there are problems with people misusing alt text fields, adding information in alt text that is unrelated to the image, or hiding “Easter eggs” in alt text that doesn’t help blind users understand the image.

Running the bots and educating people about alt text is labor that falls on individuals, like blind users and tech-savvy allies. That work, Durden says, isn’t sustainable in the long term, and many bots made years ago are now defunct, either because creators could no longer maintain them and fix issues, or because the people doing the work burnt out.

For a year, Jess Watson volunteered her time to write image descriptions for pictures on Twitter that didn’t include alt text under the handle @description_bot. Despite the name of the account, it wasn’t automated — Watson did it herself, manually, when people tagged the account.

When the workload became overwhelming, Watson was forced to stop writing descriptions, she told The Verge via email. When asked why she volunteered so much of her time and energy — even for posts she didn’t make — Watson is clear: blind and people with low vision deserve it.

“I took on the task of writing image descriptions because I felt I should do it,” Watson says, “And could do it.”