Each platform reads a caption differently
Limits and conventions differ enough that one caption rarely fits all. Instagram allows 2,200 characters but shows only the opening line or two before the 'more' cut, so the point has to come first. LinkedIn allows 3,000 characters and rewards a plain first sentence that earns the click to expand. X caps standard posts at 280 characters and counts Chinese, Japanese and Korean characters double, which halves the room in those markets. TikTok allows up to 4,000 characters, but the caption sits over the video, so short lines that add context beat paragraphs. Write a separate caption per platform from the same brief, not one caption trimmed four ways.
Hashtags, emoji and the screen reader
Platforms are cutting hashtags back: Instagram began limiting posts and Reels to five in December 2025, saying a few specific tags work better than a long generic list. Pick tags people actually search, and write them in CamelCase (#SpringLaunch, not #springlaunch) so screen readers pronounce them as words. Emoji are read aloud by their full names, so a row of five becomes a long interruption; use one or two, at the end of a line, never in place of a word. Emoji also carry different meanings across cultures and render differently across devices, so check them per market rather than copying the English set.
Alt text is a caption too
Alt text is written for someone who cannot see the image, so it describes what matters in the picture rather than repeating the caption or listing keywords. Instagram lets you replace its automatic alt text under advanced settings, X allows image descriptions of up to 1,000 characters, and LinkedIn has its own alt text field. Generated alt text is a useful first draft, but it often names the obvious and misses the point: 'a woman holding a bottle' instead of 'the new refill pouch being poured into the glass bottle'. Have the caption writer approve it, and include any text that appears in the image, such as a price or offer, because a screen reader cannot read pixels.
Where the brand voice lives, and where people take over
The studio holds tone of voice, approved claims and banned words in the brand hub, so captions in 30 languages are generated within those rules and go through the same sign-off as the visuals. What should not be automated is the conversation that follows. Replies to complaints, questions about safety or health, anything touching a crisis, and comments that could escalate need a person who can check facts and take responsibility. Automated replies that miss sarcasm or grief are how brand accounts end up in the news. Use generation for the scheduled posts; keep community management with a named team and a clear escalation path.
Updated 25 September 2026