Free tool

Will this post actually publish?

Paste your caption, drop your images, and see every network's verdict at once. Real limits, real pixel bounds, real file formats, and the exact reason when something will be refused.

Nothing leaves your browser. No upload, no account.

Your post

Images and video

Drop files here, or click to choose.
Dimensions are read in the browser. Nothing is uploaded.

    Title (TikTok photo posts and YouTube)

    What gets checked

    • Caption length against each network's real limit, using the per-post-type limit where a network has one. X is counted X's way: every link is a flat 23 characters and most emoji count double.
    • Whether media is required. Some networks refuse text on its own, and one of them refuses anything that is not video.
    • How many images fit before the rest get quietly dropped.
    • File format against each network's accepted list.
    • File weight and pixel dimensions, read from the file itself.
    • Threads and first comments, which several networks cannot do at all.

    Why the rules are so awkward

    Every network keeps its own. TikTok will not take a caption on its own and refuses PNG outright. YouTube publishes video and nothing else. LinkedIn takes images but not video on a personal profile. Instagram and TikTok publish asynchronously, so a bad file is accepted at upload and refused minutes later, long after the call came back fine.

    This tool runs exactly the checks PostLake's API runs before it publishes, read from the same registry. That is why it can be specific rather than approximate: it is not a guess at the rules, it is the rules.

    PostLake is the social media API for AI agents. One integration publishes, schedules and measures across every major network, and refuses a post that would fail before it costs you anything.

    Start free, no card
    Image size checkerDrop an image, see who accepts it, and convert it to fit in a click. Character counterCaption limits for every network, counted as you type. All free toolsEverything here, no signup on any of it.