How to post to Bluesky and Mastodon at the same time

Bluesky and Mastodon suit the same kind of post: a few lines of text, a photo, a link. So most people who use both end up writing every post twice. You don't have to.

The short version

1. Install BarlaPost on your iPhone or Android phone and create an account.
2. Connect Bluesky with an app password, and Mastodon by signing in on your own server.
3. Write the post once, tick both accounts, and tap publish — now or at a time you pick.

The rest of this guide covers the parts that trip people up.

Connecting Bluesky: use an app password

Bluesky lets other apps post for you through an app password, a separate password you create for one app and can revoke at any time without touching your real one. In the Bluesky app, open Settings → Privacy and security → App passwords, add one and name it "BarlaPost". Then, in BarlaPost, choose Bluesky, enter your handle and paste that app password.

Never give a third-party app your main Bluesky password. If you ever want BarlaPost to stop posting, deleting the app password in Bluesky is enough.

Connecting Mastodon: any server works

Mastodon isn't one site but thousands of servers, so BarlaPost asks which one you're on (mastodon.social, fosstodon.org, your own) and sends you to that server's own sign-in page. You approve access there, and you come back to the app connected. BarlaPost never sees your Mastodon password.

Writing one post that fits both

The one real difference is length. Bluesky allows 300 characters. Mastodon usually allows 500, and some servers set their own limit. A post written for Mastodon will often be too long for Bluesky.

BarlaPost's composer shows a counter for every account you've ticked, filling as you type, so you see that the post is too long for Bluesky before you publish rather than in an error afterwards. It counts each character the way the strictest platform would, so a post that fits in BarlaPost fits on Bluesky.

A few habits make one text work on both:

• Aim for 300 characters. It's a good length for Mastodon too.
• Put hashtags in the text. On Mastodon they're how people find posts; on Bluesky they work too.
• Put links at the end, so the sentence still reads if a link preview takes up the space.

Photos and video

A post can carry up to four photos or one video. Bluesky takes images up to 1 MB each, and BarlaPost scales larger photos down for it, so you don't need to resize anything first. Video goes to both platforms too, up to 100 MB (Bluesky also caps videos at three minutes).

Add alt text to your photos. Both communities care about it, and BarlaPost sends it to each platform in the field that platform uses, so screen-reader users on both sides get the description.

Mastodon's extras: who sees it, and content warnings

For Mastodon you can choose who sees the post — public, unlisted, followers only, or only the people it mentions — and add a content warning, which hides the post behind a short line until someone taps it. Mastodon counts the warning against the same 500 characters, and BarlaPost's counter takes it off for you.

Posting now or later

Tap publish to send at once, or pick a date and time to schedule it. Scheduled posts sit on a calendar in the app, where you can still edit or cancel them until they go out. The post is sent from our servers at that time, so your phone doesn't need to be on.

When one of them fails

Each account is published separately. If Mastodon is having a bad day, the Bluesky post still goes out, and BarlaPost tells you which account failed and why. You retry only the one that failed, so nobody sees the post twice.

Is there a catch?

BarlaPost is free today. It's for publishing, not for reading your timelines: you still use Bluesky and Mastodon themselves to scroll and reply. Your app password and Mastodon sign-in are stored encrypted, and you can disconnect either account at any time. The privacy policy has the details.

Want LinkedIn and X in the same post too? See how to cross-post to LinkedIn and X, or browse the features. Writing one caption for both? The free character counter shows whether it fits Bluesky’s 300 and Mastodon’s 500 at the same time.