An X post scheduler that counts before it commits
280 characters is the constraint that decides whether a cross-post survives. PostMCP checks it — along with media rules and credit cost — before anything reaches the queue, then mirrors the same idea to Bluesky, Threads and LinkedIn in one action.
Nobody asked for it. We built it anyway. Six weeks later it is the second-most used thing we ship.
Checked at pre-flight. An overrun is reported with the exact excess so you trim the X variant, not every version.
Up to 512MB. Cross-posting the same clip to Bluesky hits its 60-second wall first — reported before you queue.
X API access is priced differently upstream. Every other network costs 1. A post with a link adds 50 once.
X already schedules posts for free. Use it.
The schedule control sits next to the Post button in X’s web composer, X Pro keeps a scheduled column, and it costs nothing. For a single account posting only to X — threads included — that is the better tool, and we would rather say so than sell around it. This page is for the case it does not cover: the same idea going to X and four other networks, on a shared calendar, from code or from an AI assistant.
What this scheduler will and will not queue
Three formats it handles properly, and two it does not — worth knowing before you sign up rather than after.
Text posts
280 characters, counted at pre-flight so an overrun is caught before the post is queued rather than rejected at publish time.
One image or GIF
Uploaded natively through X’s chunked upload — initialize, append, finalize — with a status poll before the post references it.
Video
Up to 2 minutes 20 seconds and 512MB, streamed in segments and polled until X reports the media ready.
ThreadsNot yet
Not supported yet. A thread is a chain of replies, each one needing the previous post’s id — a different publishing shape from the single call we make today.
Polls and four-image postsNot yet
Not supported yet. Both need request fields the current composer does not send. If threads are your format, Typefully or Hypefury will serve you better than this.
The three networks worth mirroring to
You are already writing the hard part. These come nearly free — with the caveats that actually matter.
Almost the same length, so the X version usually needs no rewrite at all. Emoji count as one grapheme, not four bytes.
Room to add the sentence you cut. Publishes as the linked Instagram identity.
A different piece of writing. Worth generating rather than pasting.
20 credits, no card — and the arithmetic in the open
X costs 5 publishing credits per delivery where every other network costs 1, so the free plan is four X posts — or twenty deliveries if you are queueing to LinkedIn, Bluesky or Threads alongside it. Pre-flight prints the cost of every post before you commit to it. If X is the only network you publish to, X’s own scheduler is free and unlimited, and that is the honest recommendation.
Queue from a laptop or a phone — the calendar is responsive, and there is a companion app.
X scheduling FAQ
- Does X have a built-in post scheduler?
- Yes, and it is free. The web composer has a schedule control next to the Post button, X Pro keeps a scheduled column, and ads.x.com schedules promoted and organic posts from its own composer. If X is the only place you publish and you write from a desktop, the native scheduler is genuinely enough.
- How do I schedule posts on X from a phone?
- X’s scheduling control lives in the web composer rather than the mobile app, so the usual workaround is opening x.com in a mobile browser. PostMCP is a responsive web app plus an iOS and Android companion, so queueing from a phone is the same flow as from a laptop.
- How do I schedule tweets in advance here?
- Write the post, tick the X profiles that should receive it, and pick a date, time and timezone. PostMCP holds it in the queue and publishes at the slot. Until then you can edit it, drag it to another day, force-publish it early or delete it.
- Can I schedule an X thread?
- Not yet, and it is the honest gap on this page. Threads are chained replies — each post needs the id of the one before it — which is a different publishing shape from the single API call PostMCP makes today. X’s own composer schedules threads for free, and Typefully and Hypefury are built around them.
- What is the character limit and is it checked?
- 280 characters, and yes — pre-flight reports an overrun before the post enters the queue rather than letting X reject it at publish time. That matters most when the same copy is going to several networks and only X is too tight.
- Is there a free plan?
- The free plan carries 20 publishing credits and no card. X costs 5 credits per delivery against 1 for every other network, so that is four free X posts — or twenty if you are queueing to LinkedIn, Bluesky or Threads. We would rather print that arithmetic than let you find it at checkout.
- Why does X cost more credits than other networks?
- X API access is priced differently upstream, and that cost is passed through rather than absorbed into a higher base price for everyone. Pre-flight reports the exact cost of a post before you commit, so a multi-network broadcast never surprises your balance. A post containing a link adds 50 credits once, regardless of how many networks it reaches.
- Can I post video to X?
- Yes — up to 2 minutes 20 seconds and 512MB. Pass a public video URL as the media and the engine handles the chunked upload. Duration cannot be verified without decoding the file, so the limit is reported to you rather than enforced locally.
- Can I cross-post the same tweet to Bluesky?
- That is the most common reason people use this page. Bluesky’s 300-grapheme ceiling is close enough to 280 that the same copy usually works unchanged, and both go out from a single action with independent delivery tracking.
- Can an AI assistant post to X for me?
- Yes. PostMCP is a Model Context Protocol server, so Claude, ChatGPT or Cursor can draft, pre-flight and schedule X posts through the same queue — with an approval step before anything publishes.