X (Twitter) Guide: Formats, Limits and Best Practices

280 characters, media, video, polls, threads and what X's published algorithm reveals: a verified guide to posting as a brand.

Published on September 23, 2026 · Social platforms

X, formerly Twitter, is still the network for real-time news, industry debate and direct exchanges between professionals, journalists and customers. For a brand it's a channel for responsiveness and point of view more than a visual showcase. It also has one rare trait: X has published the code for its recommendation algorithm, so you can see concretely what gets measured. This guide covers limits verified in X's Help Center and developer docs, what that algorithm reveals, and a practical approach to posting well.

Formats and limits

Text

A post on X can be up to 280 characters, per the Help Center. Premium subscribers can write longer posts, up to 25,000 characters according to the Premium page, and anyone can read them.

Two counting quirks, documented in the developer docs: every link is automatically shortened and counts as 23 characters whatever its real length, and emojis plus some characters (Chinese, Japanese, Korean) count double. Media doesn't use up any characters.

Images and GIFs

A post can include up to 4 media items. According to the Help Center page on images, photos can be up to 5 MB, in GIF, JPEG or PNG. Images with an aspect ratio between 2:1 and 3:4 display in full in the timeline, without cropping. You can include only one animated GIF per post.

Video

Per the Help Center page on video, accounts without a subscription can post videos up to 140 seconds (2:20) and 512 MB. Premium subscribers can post much longer videos. On the web, video must fall within a 1:2.39 to 2.39:1 aspect ratio, a maximum resolution of 1,920 × 1,200 (or 1,200 × 1,900), 40 fps and a 25 Mbps bitrate.

Polls

A poll offers up to 4 options of 25 characters each and runs from 5 minutes to 7 days (1 day by default). Polls can't include photos.

Threads, Articles and Communities

• Threads are a series of connected posts from one person. Per X's Help Center, once a thread reaches 4 posts it's collapsed behind "Show this thread." The first post has to make people want to open it.
• Articles let you publish formatted long-form text (headings, bold, lists, images, video). They're limited to paid subscribers, per the Articles help page.
• Communities are topic-based spaces: posts are visible to everyone on X, but only members can engage, according to the Help Center.

Hashtags

X is one of the few platforms that gives clear guidance. Its hashtag help page recommends using no more than 2 hashtags per post as a best practice, even though you can technically add more. A space or punctuation mark breaks a hashtag.

What X's algorithm rewards

X publishes the code behind its For You feed in an official repository. It shows that the feed mixes posts from accounts you follow and accounts you don't, and that a single model ranks them by predicting the probability of each action: like, reply, repost, quote, share (including via DM or link), click, time spent on the post, video view and following the author. Negative actions are predicted too and count against a post: "not interested," mute, block, report, or scrolling past without stopping.

The same repository describes several adjustments worth knowing:

• Author diversity: repeated posts from the same account are progressively down-weighted so no single author floods the feed.
• New-author boost: accounts with few impressions so far get a lift.
• Freshness: posts older than 48 hours are filtered out before ranking.
• Out-of-network discount: a post shown to people who don't follow the author takes a penalty.

What that means for a brand:

• Aim for replies and shares, not just likes: a question, a clear opinion, useful information people want to pass along.
• Don't post in bursts: author diversity cuts the reach of posts bunched too close together.
• Post when your audience is active: after 48 hours, a post drops out of the recommendation feed.
• Stay relevant: negative signals such as mute, report and "not interested" pull a post down.

What a brand should post on X

• Takes on news in your industry, in a sentence or two.
• Educational threads: a 5-step method, a lessons-learned story, an analysis.
• Announcements: new products, events, availability, with a visual.
• Polls to hear from your audience.
• Replies to customers and to conversations in your space. On X, responsiveness is part of your brand.

Writing a thread people finish

A thread lives or dies on its first post. It has to say clearly what the reader will get: "How we cut our delivery times in half, in 6 steps" does more work than "A few thoughts on logistics." Remember that from four posts onward the thread collapses behind "Show this thread," so the opener is often the only thing people see.

Each following post should stand on its own, with one idea per post, since people may land on any of them through a reply or a repost. Use numbers when you walk through steps, and keep each post well under the character limit so it reads fast. Add a visual where it genuinely helps: a chart, a screenshot, a before-and-after.

Close with a summary or a question that invites replies, and put any link at the end rather than the beginning, so the thread delivers value before asking for a click. Then stay around to answer: replies are among the actions the algorithm measures.

How often to post

X doesn't publish a recommended frequency. The short lifespan of posts (48 hours in the recommendation feed) favors a steady presence over occasional posts, while author diversity penalizes bursts. A good baseline: a few posts spread across the week, plus time each day to reply.

For publishing tools, the X API caps post creation at 100 per 15 minutes per user, far beyond any editorial need.

Common mistakes

1. Forgetting that every link counts as 23 characters. A 275-character post plus a link goes over.
2. Piling on hashtags. X recommends 2 at most.
3. Posting a 3-minute video without a subscription. The limit is 140 seconds.
4. Adding several GIFs to one post. Only one is allowed.
5. Opening a thread without a hook. Past three posts, the rest gets collapsed.
6. Posting in bursts. Posts bunched together from the same account lose visibility.
7. Broadcasting without replying. Replies are one of the signals the algorithm measures.

Measuring what works

Given how short a post's life is, judge performance by type of post rather than one post at a time. Compare replies and reposts across your takes, threads, announcements and polls over several weeks. The formats that consistently start conversations are the ones to lean into, since replies and shares are among the actions X's ranking predicts.

Pre-publish checklist

• Text at 280 characters or less, with links counted as 23 and emojis counted double.
• A clear idea in the first few words.
• 2 hashtags at most.
• Up to 4 media items; images between 2:1 and 3:4 to avoid cropping.
• Video of 140 seconds or less without a subscription.
• For a thread: a first post that makes people want the rest.
• Time set aside to reply.

X as part of a multi-network routine

X calls for short, responsive posts rewritten for its format, on top of the work your other networks need. With Oposto, you describe your brand once: it learns your voice, products and audience from your website, adapts each post to each network, including X's 280 characters, plans it in a calendar and publishes it at the scheduled time. Then it measures real performance and reuses what works.

To see next month's posts ready for review, try Oposto: describe your brand once, it prepares a month of content in the right format for each network, and you approve.