Core concepts

Media

Some networks can post plain text; others need an image or video. Here's how media attaches to a post, and which networks require it.

How media attaches

Pass a media field on Create a post — a publicly reachable URL to an image or video. Networks fetch the file from that URL when they publish, so it must be openly accessible (no auth, no signed-and-expired links that lapse before publish time). The post’s has_media flag reflects whether a URL was provided.

{
  "caption": "New drop is live 🎬",
  "platforms": ["instagram", "x", "telegram"],
  "media": "https://cdn.yoursite.com/launch.jpg"
}

You host the file, for now

PostMyIsh doesn’t host uploads yet — put the file on your own storage or CDN and pass its URL. A managed upload flow (presigned URLs) is on the roadmap.

Which networks need media

Text-only networks accept a caption alone. Media-first networks can’t publish without a file:

RequirementNetworks
Media requiredInstagram, Pinterest, TikTok, YouTube
Text works; media optionalX, LinkedIn, Facebook, Threads, Reddit, Bluesky, Discord, Telegram

Publishing to a media-required network without a media URL won’t deliver on that network, even though a text-only network in the same request will. Plan your platforms list around what you’re sending.

Formats & captions

  • Each network adapts the caption to its own limits — X truncates to 280 characters, for instance. The per-network ceilings are listed on each platform guide.
  • One media URL attaches per post today — multi-image carousels and native video variants per network aren’t exposed through the API yet.

Match the file to the network

A network only accepts media types it supports — an image URL won’t satisfy a video-only surface like YouTube, and vice versa. Check the target’s platform guide for accepted formats before you send.