The feed never shows your post the way you made it
You design a post in a clean editor, full-bleed and uncropped, every word visible. Then the platform gets hold of it: it crops the image to its own shape, hides most of your caption behind “…more,” and lays its buttons and bars across the screen. The version your audience sees can be meaningfully different from the one you approved — a subject cropped out of frame, a hook that lands afterthe fold, a line of text sitting under the action buttons. This tool renders that real, post-publish version from your own image and caption, so you catch the surprise while it’s still a draft.
Front-load for the fold
Every platform truncates the caption, just at a different point — roughly 125 characters on an Instagram feed post, around 140 on LinkedIn, a line or two on a Story, about 50 on a YouTube Short. Most people never tap to expand, so whatever sits after the fold is, in practice, optional. The previewer marks exactly where your caption gets cut on the format you’re posting to, which makes the fix obvious: get the hook and the point in front of the cut. To tune the wording against the fold across every platform at once, the caption previewer does that side as plain text, with nothing else in the frame.
Keep it out of the safe zones
On vertical formats — Stories, Reels, TikTok, Shorts — the platform paints its interface over your content: the profile bar and progress dots along the top, the caption and audio strip across the bottom, the column of action buttons down the right edge. Anything you place under them is covered. Turn on the safe-zone overlay and those regions are shaded, so you keep your subject, your text, and your logo in the clear middle of the frame. To get the image itself to the right dimensions for each format before you preview, the image resizer crops to every platform’s size in one pass.
Your content, your browser
The whole thing runs locally. Your image is read from your device and drawn into the mockup in the browser; your caption never leaves the page; nothing is uploaded, stored, or seen by anyone else. That matters for the work most worth previewing — an unreleased campaign, a client deliverable, a launch you haven’t announced. Preview it as many times as you like, across every format, with zero exposure.
Frequently asked questions
What does a post previewer do?
It shows you how your post will actually look on each platform before you publish it — using your own image and caption. Every platform crops the image to a different shape, cuts your caption off at a different point, and covers part of the screen with its own buttons and bars. A previewer renders a realistic mockup of all that, so you catch a subject that gets cropped out, a caption whose hook lands after the fold, or text sitting behind the action buttons — while you can still fix it, not after a hundred people have seen it.
Is my image or caption uploaded anywhere?
No. Everything runs in your browser: your image is read from your device and rendered locally, your caption stays on the page, and nothing is sent to a server or saved. There's no account and no history. That's the whole design — the tool only ever touches the photo and text you give it, which means you can safely preview unreleased or client work.
Where does my caption get cut off?
It depends on the format, which is why this tool shows the fold per platform. An Instagram feed caption truncates at about 125 characters behind “…more”; a TikTok caption shows around 150; a LinkedIn post folds near 140 behind “…see more”; an Instagram Story shows only a line or two; a YouTube Short title shows about 50 characters. The rule that survives all of them: put your hook and the thing people must read before the fold, and treat everything after it as bonus for the few who tap. The previewer marks exactly where each one cuts.
What are the safe zones?
On full-screen vertical formats — Stories, Reels, TikTok, Shorts — the platform overlays its own interface on top of your content: a profile bar and progress dots up top, a caption and audio strip along the bottom, a column of action buttons down the right. Anything you place under those gets covered. The previewer shades those regions so you keep your subject, your text, and your logo out of them. It's the single most common mistake in vertical video, and it's invisible until you see the overlay.
How is this different from the caption previewer?
They answer different questions. The caption previewer is text-only — paste a caption and see the exact character where each platform folds it, with nothing else in the way; it's the fastest way to check fold points across every platform at once. This post previewer is visual — it builds the whole mockup with your image, the platform's chrome, and the safe-zone overlays, so you see the finished post, not just the text. Use the caption previewer to tune the wording; use this to check the whole thing looks right.
Which platforms and formats does it cover?
It covers 12 formats across the major platforms — Instagram feed, Story, Reel, and carousel; TikTok; YouTube Shorts; X; LinkedIn; Threads; a Pinterest Pin; and Facebook feed, Story, and Reel. Each one uses that format's real aspect ratio, caption fold point, and safe zones, so switching between them shows how the same image and caption land in each place — which is exactly what you need when you're repurposing one post across several platforms.