If you're looking for somewhere to post besides X, there are three main options, and they're very different under the hood. Threads is Meta's, big and algorithmic. Bluesky is an open network with feeds you choose. Mastodon is a federation of independent servers with no algorithm at all.
This guide compares them for people who post, not just people who scroll: who's there, how posts get seen, what you can post, and how to schedule. It was written on 25 October 2026. User numbers change quickly and are estimates, so treat them as rough.
At a glance
| Threads | Bluesky | Mastodon | |
|---|---|---|---|
| Run by | Meta | Bluesky Social (on the open AT Protocol) | Thousands of independent servers |
| Audience size | Largest, by far (hundreds of millions monthly) | Mid-sized (around 10 million monthly mobile users, 40 million+ accounts) | Smallest (well under a few million active) |
| Main feed | Algorithmic "For you" | Chronological Following, plus feeds you choose | Chronological, no algorithm |
| Characters per post | 500 | 300 | 500 on most servers |
| Images per post | Up to 20 | Up to 4 | Up to 4 |
| Links | Allowed, shown as cards | Allowed, shown as cards | Allowed; count as 23 characters |
| Hashtags | One topic tag per post | Supported, lightly used | Essential for discovery |
| Built-in scheduling | Yes | No | No (API only) |
| Sign-up | Instagram account or standalone | Email; handle can be your own domain | Pick a server, then sign up |
| Leaving with your followers | No | Yes, via the open protocol | Yes, move to another server |
Who's actually there
Threads has the biggest audience by a wide margin, much of it brought over from Instagram. It's broad: lifestyle, sport, entertainment, creators and brands. If your audience is on Instagram, a lot of it is on Threads.
Bluesky grew fast in 2024 and has shrunk since its peak, according to third-party estimates, but it still has a large and very engaged core. It's strong for journalists, scientists, academics, artists, writers, politics, and parts of tech. People there tend to read and reply rather than scroll past.
Mastodon is the smallest, and the most community-driven. It's strongest in open source, software, privacy, academia, and niche hobbies, often on servers built for those communities (fosstodon.org, hachyderm.io and so on). Engagement per follower is often high, but the ceiling is low.
How your posts get seen
This is the biggest difference between them, and it decides what kind of posting works.
Threads works like Instagram: an algorithm decides what people see, and a post from someone they don't follow can go far if it gets early engagement. Good for reach from zero; less predictable.
Bluesky lets people choose. The default Following feed is chronological, and there are thousands of custom feeds built by users around topics ("Science", "Book Sky", "Dev"). Getting into the right custom feeds and starter packs is how new accounts grow. More in our guide to growing on Bluesky.
Mastodon has no algorithm. Posts appear in followers' timelines in the order they're published, and people find new accounts through hashtags, boosts and server-wide timelines. Growth is slower but steady, and timing matters more because nothing is resurfaced.
Which should you choose?
| If you are… | Start with |
|---|---|
| A creator or brand that wants the most reach | Threads |
| Coming from Instagram | Threads |
| A writer, journalist, researcher or artist | Bluesky |
| Building in public, in tech or AI | Bluesky, then Mastodon |
| In open source, privacy or a niche community | Mastodon |
| Someone who wants to own their audience | Bluesky or Mastodon |
| Not sure | Bluesky and Threads, cross-posted |
You don't have to choose just one. Many people post the same idea to two or all three, adjusted for each. The real cost is replies: each network you add is another place to check comments.
Posting to more than one
The networks are similar enough that one draft can cover all three, but different enough that a straight copy looks lazy:
- Length: Bluesky's 300-character limit is the tightest, so write that version first, or split it into a short thread.
- Hashtags: use one or two in CamelCase on Mastodon, where they matter; few or none on Bluesky; one topic tag on Threads.
- Handles: don't leave an @handle from one network in a post on another.
- Thread markers: "1/5" looks out of place on Mastodon and Bluesky; a short first post that makes people tap is better.
Our guide to cross-posting without it looking copy-pasted goes into more detail.
Scheduling on each
- Threads has its own scheduler in the composer, for single posts.
- Bluesky has no scheduler in its app. You need a tool; here's how to schedule Bluesky posts.
- Mastodon has scheduling in its API but not in its official apps. Here's how to schedule Mastodon posts.
Postbase schedules posts and threads to Bluesky and Mastodon (any server), alongside X, LinkedIn, TikTok and YouTube. You write once, adjust the wording for each network in its own tab, and each limit is checked as you type. Threads is coming soon; until then, use Threads' own scheduler for it.
Available channels
Customize per channel
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The verdict
- Threads for reach. The biggest audience and an algorithm that can show you to strangers. Best if your audience is already on Instagram.
- Bluesky for conversation. A smaller but engaged audience, real control over feeds, and you keep your followers if you ever leave.
- Mastodon for community. The smallest, slowest-growing and most loyal. Best if your niche already lives there.
If you can only manage one, pick the one where the people you want to reach already are. If you can manage two, Bluesky plus Threads covers most audiences, with Mastodon as a third if you're in tech or open source.
Frequently asked questions
Is Bluesky bigger than Mastodon?
Yes. Bluesky has more than 40 million registered accounts and around 10 million monthly mobile users by third-party estimates in 2026. Mastodon's active users across all servers are far fewer.
Is Threads bigger than Bluesky?
Yes, by a wide margin. Meta has reported hundreds of millions of monthly Threads users, many times Bluesky's active audience.
Can Bluesky, Mastodon and Threads talk to each other?
Partly. Threads can share posts to the fediverse, where Mastodon users can follow them, if the Threads user turns it on. Bluesky uses a different protocol, though bridge services can connect it to Mastodon for accounts that opt in.
Which is best for businesses?
Threads for consumer brands that want reach, especially those already on Instagram. Bluesky for media, B2B and tech brands that want conversation. Mastodon for open-source and developer-focused projects.
Can I schedule posts on Bluesky and Mastodon?
Not in their official apps. Use a scheduling tool such as Postbase, which posts through each network's official API, including threads.
Should I post the same thing on all three?
The same idea, adjusted for each: Bluesky's limit is 300 characters, Mastodon and Threads allow 500, and hashtag habits differ. A tool that lets you write once and adjust per network makes this quick.
Postbase