Bluesky and X look alike on the surface: short posts, replies, reposts, a feed. The difference is who decides what you see. X ranks one main feed, For You, with a model it runs for everyone. Bluesky lets each person pick feeds and moderation filters, many of them built by other people. X is far larger; Bluesky had 41.41 million accounts at the end of 2025. Post where your readers already are, and use the other one second.
Key Takeaways
- Length: a Bluesky post holds 300 graphemes. X’s developer docs set 280 characters for a post, with every link counted as 23 and every emoji as 2.
- Feeds: X’s For You mixes accounts you follow with accounts you do not, ranks them with one transformer model, and blends in ads. On Bluesky anyone can build a feed, and people pin the ones they want.
- Moderation: Bluesky runs its own moderation and lets users add independent moderation services on top. X decides visibility with its own filtering system.
- Openness: X publishes the code for its For You feed on GitHub. Bluesky publishes the protocol that the whole network runs on, and accounts can live on servers Bluesky does not run.
- Size: Bluesky reported 41.41 million accounts at the end of 2025. X’s ad tools reported 586 million users reachable with ads in January 2025. The two figures measure different things, but the gap is large.
Bluesky vs X at a glance
The table compares the two on the points that change how you post. Every row comes from the platform’s own code, documentation or reports, read in October 2026.
| Bluesky | X (Twitter) | |
|---|---|---|
| Post length | 300 graphemes | 280 characters; links count as 23, emoji as 2 |
| Images per post | Up to 4, each up to 2 MB | Supported |
| Main feed | Following, Discover, plus any custom feed you pin | For You: followed and non-followed accounts, ranked by one model |
| Who builds feeds | Anyone | X |
| Ads in the main feed | None described in Bluesky’s documents | Yes, blended into For You |
| Moderation | Bluesky’s own, plus subscribable independent services | X’s visibility filtering |
| Open code | The AT Protocol network | The For You feed (Apache 2.0) |
| Reported size | 41.41M accounts, end of 2025 | 586M ad-reachable users, January 2025 |
| Scheduling in the official app | No schedule option in the composer | See our guide below |
What is the difference between Bluesky and X?
X is one company running one network with one main ranking system. Bluesky is a company running the largest app on an open network called the AT Protocol, where feeds, moderation and even the servers that hold accounts can come from other people. On X you tune the algorithm by how you behave. On Bluesky you also choose which algorithms and filters you use.
The practical difference shows up in the feed itself. X’s For You is ranked by X from posts it predicts you will engage with. Bluesky gives new accounts a few default feeds, Discover among them, and the feed list can hold many more: feeds built around one profession, one hobby or one community, each run by whoever made it.
Bluesky’s 2025 transparency report counts its 41.41 million accounts across “thousands of Personal Data Servers operated by people across the federated AT Protocol network, with the majority hosted independently by third parties.” That is a structural fact about the network. Your Bluesky account is not tied to Bluesky the company in the way an X account is tied to X.
How do the feeds rank posts on each platform?
X ranks For You with a single model that predicts how likely you are to like, reply, repost, click, dwell, follow, or block and report each candidate post, then adds those predictions into one score. On Bluesky, any feed beyond Following and Discover runs on rules chosen by whoever built it. The ranking you face on Bluesky depends on which feed a reader has open.
X has published the current For You code on GitHub since January 2026 (an older version went public in 2023), in a repository updated as recently as October 2026. Its README describes the feed as posts from accounts the viewer follows plus posts found by retrieval models from accounts they do not, all ranked together. A few rules in it matter to anyone posting:
- Posts older than 48 hours are dropped from For You candidates by an age filter. X’s main feed is a short-lived window.
- Out-of-network posts are discounted. Posts from accounts the viewer does not follow are multiplied by a factor below 1, so your followers remain your strongest audience.
- New authors get a lift. Posts from authors whose impressions are below a threshold are moved toward a target position.
- Negative signals count. “Not interested”, mute, block, report and “not dwelled” all carry negative weight.
- One author at a time. Each post after an author’s first in the same feed is multiplied by a decaying factor.
When Bluesky launched Discover in July 2023, its team said the initial version “mixes in a global view of what’s trending in the network with posts from accounts you follow and posts from accounts near your social graph,” and promised to keep improving it. We found no newer public description of how Discover ranks posts. Custom feeds are the bigger story: “On Bluesky, anyone can create a feed,” Bluesky wrote, and people pin and sort the feeds they use. Because anyone can build a feed, a post can also reach readers through a niche feed run by someone else, on rules that person chose. Our guide to how the X algorithm works covers the older, 2023 version of X’s published code in more depth.
How does moderation differ between Bluesky and X?
Bluesky moderates the app itself and lets each person add more moderation services on top, run by independent groups. X moderates centrally: its open-source code shows a visibility system that decides whether a post can be shown at all, separate from ranking. Neither approach is hands-off. They differ in who gets to add rules.
Bluesky opened independent moderation services in March 2024. In its words, people can “install filters from independent moderation services, layering them like building blocks on top of the Bluesky app’s foundation.” These services attach labels to posts and accounts, and the reader’s settings decide whether a labelled post is hidden, blurred or shown. In 2025 Bluesky applied 16.49 million labels itself, up from 5.5 million in 2024, according to its transparency report, while account takedowns rose from 1.02 million to 2.08 million.
On X, the For You README says ranking sets the order and visibility filtering “decides whether a post can be shown at all”, using the viewer’s own blocks and mutes and labels attached by other systems. X is piloting a tool called Under the Hood that shows account owners aggregate statistics about visibility-affecting labels on their account and posts. For a brand or creator, that is the place to look when reach drops without explanation.
Which is better for creators and brands?
X is better when your audience is already there and you need size: its ad tools report hundreds of millions of reachable users, its feed shows posts to non-followers, and it supports threads, polls and ads. Bluesky is better for communities that left X or never joined it, and for anyone who wants niche feeds to carry posts to interested readers rather than one ranking system.
A few concrete cases:
- Your audience left X or never joined it. Check Bluesky first, and search its feed list for your field. A custom feed built around a topic can put a post in front of exactly the people it was written for.
- You need reach for news, sport, crypto or consumer launches. X’s larger audience is the reason to be there, and its For You feed mixes in posts from accounts people do not follow, as long as the post is under 48 hours old.
- You already have an audience on X. Keep posting there and test Bluesky with the same ideas rewritten for 300 graphemes. A month of posts on both tells you more than any comparison.
- You rely on paid promotion. X sells ads inside For You. Bluesky has not described an ad product in the documents we read, so organic posts are the only lever there.
Do not judge either platform by its headline size alone. An account count says nothing about how many of those people care about your topic. Measure replies and clicks on your own posts, not followers.
Can you schedule posts on Bluesky and X?
Bluesky’s own app has no schedule option in its composer, so scheduling needs a third-party tool that signs in with an app password. X has its own scheduling options in some of its apps; check what yours offers before you rely on it.
Our guides walk through both: how to schedule Bluesky posts step by step, and how to schedule tweets on X on the web, on mobile and with tools.
The connection method differs, and it matters for security. A Bluesky scheduler uses an app password, a separate password you create in Bluesky’s settings and can revoke at any time without changing your main one. An X scheduler connects through X’s official API with OAuth 2.0, so you sign in on X and the tool never sees your password.
How does PostNext handle posting to both?
PostNext schedules X and Bluesky from the same calendar, with different capabilities on each. On X it publishes posts and full threads with media, schedules polls with 2 to 4 choices, and on paid plans suggests three posting slots from your own last 90 days. On Bluesky it publishes text posts with up to four images, each post on its own.
The X side is described in full on the PostNext X scheduler page. Bluesky threads, replies and video are not supported in PostNext, so post those in the Bluesky app. The scheduler can duplicate a post across channels, which is the quickest way to adapt an X post for Bluesky: duplicate it, then trim or rewrite it for the 300-grapheme limit and the different crowd. To check length on the X side, use the free Twitter character counter, and the Bluesky post formatter helps with line breaks and styling before you paste.
The free plan covers one channel and 10 posts a month, which is enough to test one platform. Connecting both X and Bluesky needs a paid plan, and every new account starts with a 7-day trial.
For a wider look at where each network stands, see the most popular social media platforms and our guide to choosing the right social media platform.
Frequently Asked Questions
Is Bluesky better than X?
Neither is better for everyone. X is much larger and better for broad reach and paid promotion. Bluesky suits communities that want to choose their own feeds and moderation, and its custom feeds can put niche posts in front of the right readers.
How many people use Bluesky compared with X?
Bluesky reported 41.41 million accounts at the end of 2025. X’s ad tools reported 586 million users reachable with ads in January 2025. The figures measure different things, accounts against ad reach, so compare them as an order of magnitude, not exactly.
What is the character limit on Bluesky vs X?
A Bluesky post holds 300 graphemes. X’s developer documentation sets 280 characters for a post, counts every link as 23 characters and every emoji as 2, and weights Chinese, Japanese and Korean characters as 2 each.
Can you cross-post between Bluesky and X?
Yes, with a scheduler that supports both. PostNext publishes to X and Bluesky from one calendar and can duplicate a post across channels, so you can adapt the text for each platform’s length and audience before it goes out.
Does Bluesky have an algorithm?
Yes, several. Discover is Bluesky’s own feed, Following shows accounts you follow, and anyone can build and publish a custom feed with its own rules. Readers choose which feeds to pin.
Is X’s algorithm open source?
Yes. X publishes the code for its For You feed on GitHub under the Apache 2.0 licence. The repository describes how posts are retrieved, filtered, scored and ranked, and it was last updated in October 2026.
Related reading
- How to Schedule Bluesky Posts in 2026
- How to Schedule Tweets on X
- X (Twitter) Algorithm Explained in 2026
- The Most Popular Social Media Platforms
- Choosing the Right Social Media Platform
Sources
- X, X For You Feed Algorithm, repository README (github.com/xai-org/x-algorithm, created January 2026, read October 2026)
- X Developer Platform, Counting characters (October 2026)
- Bluesky, AT Protocol lexicons for posts and images (
feed/post.json,embed/images.json, October 2026) - Bluesky, Bluesky 2025 Transparency Report, 29 January 2026 (read October 2026)
- Bluesky, Algorithmic Choice with Custom Feeds, 27 July 2023 (read October 2026)
- Bluesky, Bluesky’s Stackable Approach to Moderation, 12 March 2024 (read October 2026)
- DataReportal (Kepios), Essential X statistics, on X ad reach in January 2025 (read October 2026)
- PostNext, postnext.io/x-scheduler and postnext.io/features/scheduling (October 2026)
