Cross-post Mastodon to Bluesky, automatically
Connect both accounts once. Every new Mastodon post you make is republished to Bluesky in under a second, with replies, quotes and paid posts stopped by default.
Every figure on this page is read at build time from the same file the splitter and the rules engine read, so it cannot drift from what the product actually enforces. Limits last verified 27 August 2026.
The reason
Why cross-post from Mastodon to Bluesky
You already post on Mastodon. The audience on Bluesky is a different set of people, and they see none of it unless you do the work twice — export, re-upload, rewrite the caption to fit, remember the alt text. That second pass is what stops happening in a busy week, and the Bluesky account goes quiet for reasons that have nothing to do with what you are making.
Mastodon gives you 500 characters and Bluesky gives you 300 characters, which sounds like a detail until it is the reason half your posts arrive truncated or not at all. Echowide reads both numbers from the same file the splitter uses, so a post that fits is published whole and a post that does not is either threaded or stopped, with the count written down.
Echowide does the second pass. It watches Mastodon, decides whether each post should travel, fits it to Bluesky, publishes it, and records what happened — including the failures, in the platform's own words. It is not a scheduler: you post where you were already going to post.
Side by side
What Bluesky does differently
Bluesky is the tighter of the two: 300 characters against Mastodon's 500. That is the number that decides what happens to your longer posts, and it is the reason threading is on by default on this pair.
| Limit | Mastodon (origin) | Bluesky (destination) |
|---|---|---|
| Characters per post | 500 | 300 |
| Long posts | native thread | native thread |
| Video cap | no published cap | 3 minutes |
| Images per post | no verified image count | up to 4 images |
| How Echowide sees a new post | pushed to us on a socket we hold open | pushed to us on a socket we hold open, when it is the origin |
Mastodon character limit in fullBluesky character limit in fullMastodon on the full platform tableBluesky on the full platform table
The carry list
What gets carried across, and what stops
- Textcarried
- Up to 300 characters go across as written. Longer than that and the splitter breaks it at a paragraph, then a line, then a sentence — never mid-word, never mid-URL — and posts it as a native Bluesky thread.
- Images and alt textcarried
- Bluesky takes up to 4 images, and alt text travels with each one. We do not invent a description for a photograph you did not describe.
- Videocarried
- Bluesky caps video at 3 minutes, which is at or above what Mastodon will hand us, so length is rarely the thing that stops a video on this pair.
- Threads and self-repliescarried
- A thread you wrote yourself on Mastodon is rebuilt as a real Bluesky chain, in order, each part replying to the last.
- Replies to other peoplestops
- Stopped by default: a reply carries half a conversation your Bluesky audience cannot see. Replies to yourself do travel.
- Quotes of other peoplestops
- Stopped by default: quoting a stranger republishes them to an audience that never chose to hear from them. Quoting yourself travels.
- Posts tagged #ad or #brandpartnerstops
- Stopped by default and switchable per flow. A disclosure that fails to travel with the post is a regulatory problem, not a formatting one. Tags: #ad, #brandpartner, #sponsored, #paidpartnership.
- Posts tagged #noferry or #noechostops
- Your own switch. Either tag anywhere in the post means "not this one". One of the two is the convention creators already have from other tools, so we honour it as well as ours.
Measured, not promised
How fast it is
Mastodon to us
under a second
Mastodon pushes; we are already listening
Mastodon pushes to us on a socket we hold open, so the echo leaves in under a second. There is no interval here to shorten, because there is no interval: we are subscribed before you press post, and your post arrives as an event rather than as the answer to a question we asked.
What is left is Bluesky's own publish call, which usually takes longer than everything upstream of it. It is not a plan feature either: the socket costs us one connection for every Mastodon account in the world rather than one per customer, so the free plan gets the same second.
Setup
Set it up in three steps
- Step 1
Connect Mastodon as the origin
Mastodon signs in through your own instance, so your instance's admin sees the grant and you can withdraw it there. We ask for the narrowest scope that lets us read your own posts, and the credential goes into an encrypted vault — never a log line.
- Step 2
Connect Bluesky as the destination
Bluesky needs a revocable app password, not your account password, and you can revoke it from Bluesky without touching us. A destination can never also be the origin of the same flow, so there is no way to build a loop that echoes into itself.
- Step 3
Dry run, then switch it on
A dry run replays your recent Mastodon posts through the rules engine and shows what would have reached Bluesky and what would have stopped, with the reason for each. Nothing publishes. When the list looks right, switch it on.
Fail closed
What we refuse to do
The rules the engine applies before anything reaches Bluesky, in the order it applies them, read from the file the engine itself runs — so this list cannot describe a rule the product does not enforce.
- Replies to other people
- A reply to somebody on Mastodon stays on Mastodon: your Bluesky followers would see one half of an exchange with no way to read the other. A reply in your own thread does go.
- Quotes of other people
- A quote post republishes somebody else's words to an audience they did not choose. We carry quotes of your own posts and stop the rest. There is no setting that turns this into "quote everybody".
- Anything tagged #ad or #brandpartner
- Paid posts stop by default: #ad, #brandpartner, #sponsored, #paidpartnership. Disclosure rules differ by country and by platform, and a disclosure that arrives on Mastodon but not on Bluesky is worse than not cross-posting at all. Switchable per flow.
- Over-limit posts, when you have turned threading off
- Bluesky allows 300 characters and has real threads, so by default a longer post becomes a native chain. Turn threading off and a longer post stops instead — with the count and the limit in the ledger. We will not truncate your writing and publish the first half under your name.
- Instagram Trial Reels
- A Trial Reel is hidden from your own followers on purpose — that is the whole point of it. Cross-posting one defeats the reason you made it, so when Instagram is the origin, Trial Reels never leave.
- Anything we are not sure about
- The rules engine fails closed. If an adapter cannot tell us whether a post is a reply, or how long its video is, the answer is no and the ledger says which fact was missing. A missed cross-post is a click to fix; an unwanted one is public and permanent.
- Anything you tagged #noferry or #noecho
- Put either tag anywhere in a post and it stays where you wrote it. You can also set your own phrase per flow. This is checked before everything else, so it overrides every other rule on this page.
Questions
Frequently asked questions
- Can Echowide post from Mastodon to Bluesky automatically?
- Yes. Connect Mastodon as an origin and Bluesky as a destination, and every new Mastodon post is republished to Bluesky without you doing anything else. Nothing is queued or scheduled here.
- How long does a Mastodon post take to appear on Bluesky?
- Mastodon pushes new posts to us on a connection we hold open, so the echo leaves in under a second and the remaining time is Bluesky's own publish call. This is the same on the free plan.
- What happens to a post that is too long for Bluesky?
- Bluesky allows 300 characters and supports real threads, so a longer post is split at a paragraph, line or sentence boundary — never mid-word, never mid-URL — and published as a native chain. Turn threading off and it stops instead, with the count and the limit recorded.
- Does it cross-post my replies and quote posts?
- Not to other people. A reply to, or quote of, somebody else stops by default — your Bluesky audience would see one side of a conversation. Replies within your own thread and quotes of your own posts travel. Posts tagged #ad or #brandpartner stop as well.
- Does video carry from Mastodon to Bluesky?
- Yes, up to 3 minutes, which is Bluesky's own cap and is at or above what Mastodon will hand us. Alt text and captions travel with it where both platforms support them.
- What does cross-posting Mastodon to Bluesky cost?
- Nothing for the first fifty cross-posts a month, then $9. There is no per-channel pricing and no faster tier: the speed on this pair depends on whether Mastodon pushes to us, not on what you pay. No card to start.
Post on Mastodon. We will handle Bluesky.
Free for the first fifty cross-posts a month, then $9. Run a dry run before anything publishes, and read the ledger afterwards to see exactly what each platform did with your post, in its own words.