Social Media Post Preview

See your post before you publish

A social media post preview tool renders your draft caption and image inside mockups of each platform's feed layout, so you can see the composition, the aspect-ratio crop, and - most importantly - the exact point where the platform truncates your text behind a “see more” link. The same 300-word caption is a complete post on LinkedIn, a two-line teaser on Instagram, and impossible on X.

The two numbers that matter per platform are the hard limit (what the composer will accept) and the fold (how much shows before truncation). They are not the same, and the fold is what determines whether anyone reads you:

• X / Twitter - 280-character limit for standard accounts; effectively no fold, so every character is visible
• Instagram - 2,200-character caption limit, but the feed shows roughly the first 125 characters before “… more”
• LinkedIn - 3,000-character limit, folded at around 210 characters on desktop and fewer on mobile
• Facebook - 63,206 characters allowed, folded at roughly 480
• TikTok - 2,200-character caption, but only a line or two overlays the video
• YouTube community posts - 5,000 characters, with a “Read more” cut partway down

What to check before you publish

Front-load the hook. Because every fold lands within the first two lines, the opening sentence has to carry the whole post. Write it to work standing alone, then let the body expand on it. Watch the crop. A 16:9 image that looks fine on X gets center-cropped to 1:1 or 4:5 on Instagram, which regularly decapitates people or cuts text off a graphic - preview the same asset in every frame before committing. Mind the emoji and line breaks. Most emoji are two UTF-16 code units and count double against X's limit, and Instagram collapses consecutive blank lines in some clients, so a carefully spaced caption can arrive as a wall of text.

One caveat worth stating plainly: these previews are faithful approximations, not pixel-perfect clones. Platforms ship UI changes constantly and A/B-test layouts across user cohorts, so treat the mockups as a reliable guide to truncation points and framing rather than a guarantee of exact rendering.

Nothing you paste or upload leaves this tab. The captions are held in React state and images are read with the browser's FileReader API into a local object URL - no upload endpoint exists, so drafts of unpublished campaigns stay on your machine.