Overview

Four networks and one self-hosted hub platform, one API. The differences you have to design around are limits, media rules and whether first comments work — everything else behaves identically. The practical consequence of that table is that a single content string has to satisfy every target you send it to. Two ways to handle it:

• Write to the strictest limit. 280 characters satisfies every network.
• Send separate requests per network. More calls, but each gets copy that fits — which is usually what you want anyway, since a post that reads well on LinkedIn rarely does on Threads.

firstComment is already per target, so the comment can differ even within one request.

• Instagram — professional accounts, JPEG only, Reels and carousels
• Threads — text-only posts, carousels, replies as comments
• X — no comments, and the one network where a link changes the price
• LinkedIn — personal profiles and company pages
• Supa Hub — self-hosted Supa Social communities, connected with an API key instead of OAuth

Every published target's current engagement — views, likes, comments, shares, saves — is readable live with GET /api/v1/posts/:id/metrics, with the same per-target result shape as publishing. Support and caveats differ per platform (Instagram and Threads need reconnection for insight permissions on older connections; X needs a read-capable API tier; Supa Hub has no metrics surface) — see the .