Accessible Social Posts: Alt Text, Captions, and the Details Most Brands Skip

Most social accessibility advice fails for the same reason most content advice fails: it arrives as a moral lecture with no workflow attached. You read that you should be writing alt text, feel vaguely guilty, publish the post anyway, and never think about it again until the next reminder.

So let's skip the lecture. Accessibility on social is a short list of concrete habits, most of which take under a minute per post. They also happen to make your content perform better for everyone — captions get watched on mute, alt text gives the platform more context about your image, high-contrast text survives a sunny bus stop. The accessible version is usually just the clearer version.

Here's the checklist, roughly in order of how much it matters.

1. Caption your videos — all of them

If you only do one thing from this post, do this one. A huge share of social video is watched with the sound off, in public, on a phone. Captions aren't a niche accommodation; they're the default viewing mode.

Two kinds exist and they're not interchangeable:

• Auto-captions generated by the platform. Free, instant, and roughly 90% accurate — which sounds fine until the 10% lands on your product name, your pricing, or a word that changes the meaning of a sentence.
• Uploaded or edited captions that you've actually read through. This is the version to aim for on anything that matters.

The practical compromise: let the platform auto-generate, then spend 60 seconds reading the transcript and fixing proper nouns, numbers, and anything that got mangled. Brand names are the usual casualty.

Two more things people forget. Burned-in captions (baked into the video pixels) can't be turned off or translated, and they get cropped on platforms that reframe your video — so if you burn them in, keep them well inside the safe area and away from the bottom edge where the UI sits. And if your video has no speech but carries meaning through sound, say so in the caption text.

2. Write alt text that describes, not decorates

Alt text is the short description screen readers announce in place of an image. Every major platform supports it; almost nobody fills it in.

The mistake isn't skipping it — it's writing it badly. Good alt text answers one question: what would someone need to know about this image to follow the post?

• Bad: "image of our product" — tells no one anything.
• Also bad: "Stunning new launch 🔥 shop now link in bio #newdrop" — that's your caption pasted into the wrong field.
• Good: "A matte black water bottle on a kitchen counter, next to a cutting board with sliced lemons."

A few rules that make this fast:

• Lead with the subject, then the context. Don't build suspense.
• Don't start with "image of" or "photo of." The screen reader already said it's an image.
• Transcribe text in the image. If your carousel slide says "3 ways to cut your posting time," that sentence belongs in the alt text, verbatim. This is the single most commonly broken rule, and it's the one that locks people out of infographics and quote cards entirely.
• Keep it to a sentence or two. Describe what's relevant, not every object in frame.
• Skip purely decorative images. If a background texture carries no information, it doesn't need a description.

For a carousel, write alt text per slide. Slide 4 isn't described by slide 1.

3. Make your on-image text actually readable

Plenty of inaccessible social content is inaccessible for ordinary visual reasons, not assistive-tech ones.

• Contrast. Light grey text on a white card, or white text over a busy photo, fails for a lot of people and is annoying for everyone else. If you can't read it at arm's length on a phone at half brightness, it's too low.
• Size. Design for the feed, not for your 27-inch monitor. A line that looks elegant in the editor can be four pixels tall in someone's thumb-scroll.
• Don't rely on color alone. "The green one is the good plan" means nothing to a colorblind reader. Label it.
• Leave room. Text crammed to the edges gets cropped by platform UI and by different aspect ratios.

4. Fix the small text habits

These are the ones that feel pedantic until you hear a screen reader read a post out loud.

• Hashtags: use CamelCase. #SmallBusinessMarketing is parsed as four words; #smallbusinessmarketing is read as one long unpronounceable string. Capitalizing each word costs nothing and helps sighted readers too.
• Emoji: at the end, and sparingly. Every emoji is read aloud by its full name. One 🎉 is a nice flourish. Eight 🎉🎉🎉🎉 is "party popper party popper party popper party popper" in the middle of your sentence. Never use an emoji as a replacement for a word you need.
• Skip the fancy Unicode fonts. Those 𝓼𝓬𝓻𝓲𝓹𝓽 and 𝐛𝐨𝐥𝐝 characters you paste in to make a caption stand out are mathematical symbols, not letters. Screen readers either skip them or read them character by character as "mathematical bold small a." They also break search and copy-paste.
• Write real link text. On platforms where you can, avoid "click here" — say where it goes.
• Don't bury the point in a wall. Short paragraphs and line breaks help cognitive load as much as anything else on this list.

5. Build it into the workflow, not your willpower

Everything above is easy in isolation and impossible to sustain if it depends on remembering at the moment you hit publish. Three things make it stick:

Put it in your definition of done. If you have an approval step — a teammate, a co-founder, a client — add two checks to it: captions reviewed, alt text written. A post without them doesn't get approved. That's it. Accessibility becomes a checklist item rather than a virtue.

Let AI do the first draft. This is a genuinely good use for it. Hand a model your image and ask for a one-sentence factual description, then edit — you'll usually keep most of it and fix the specifics only you know. Same for cleaning up an auto-generated transcript, or rewriting a caption that's drifted into a wall of text. What AI shouldn't do is publish unreviewed: a model confidently describing the wrong thing is worse than no description, because nobody downstream can tell.

Write down your rules once. Three lines in whatever doc holds your brand voice — "CamelCase hashtags, max two emoji, alt text on every image including carousel slides" — means the rule survives a new hire, a freelancer, and your own bad week.

Why this is worth the minute

There's an argument for doing this because roughly one in six people lives with some form of disability and shutting them out of your content is both a business loss and a bad look. That argument is true and sufficient.

But the self-interested version is almost as strong. Captions increase watch time on muted autoplay. Alt text gives platforms real text to index. High-contrast, well-sized type survives being seen in bad light on a cracked screen. Readable paragraphs get read.

This is the pattern with most accessibility work: the constraint makes the content better. The post that works for a screen reader is the post with a clear subject and a stated point. That's the post you wanted to write anyway.

At Trendly we're building for the part of social that happens around publishing — planning what to post, drafting it with AI, reviewing it with your team, scheduling it everywhere, and handling the replies. Accessibility sits naturally inside that: it's one more thing the review step should catch, and one more place a first draft from AI saves you time you'd otherwise spend not bothering.

Start with captions on your next video and alt text on your next carousel. Two habits, under two minutes, and you've covered most of the gap.